Abstracts of papers presented at the 7th International Symposium of Scale Insect Studies (ISSIS-VII)

M E E T I N G S

ABSTRACTS OF PAPERS PRESENTED AT

T H E 7TH I N T E R N A T I O N A L S Y M P O S I U M OF S C A L E I N S E C T STUDIES (ISSlS-VII)

June 12-17, 1994 ARO, The Volcani Center, Bet Dagan, Israel

A: SYSTEMATICS AND MORPItOLOGY

Intraspecific Variation in the Scale Insects (Homoptera: Coccinea)

Evelyna M. Danzig Zoological Institute, Russian Academy of Sciences, St. Petersburg 199164, Russia

The range of intraspecific variation in scale insects is often remarkably wide, and is favored by polyphagy, parthenogenesis and wide distribution of several species. Variation is displayed in both morphological and biological characters. Many morphs have been described as separate species.

Variations often depend on nutritional factors. The external appearance of Parthenolecanium corni (Bouch~) and other soft scales depends on their host plants. In some armoured scales, Chionaspis, Lepidosaphes, related genera, and also in Diaspidiotus ancylus (Putnam), polymorphism is determined by the part of the plant on which the insects feed - leaf and stem forms. Transfer experiments of insects to new host plants, or from one part of the plant to another, have shown the transformation of one host-induced form to others. Biological variation may occur on different plants, e.g. sex ratio in Ericerus pela (Chavarmes), and sex ratio and phenology in Pulvinaria betulae (L.).

In P. corni, polymorphism is combined with heterogeneity of populations in sex ratio and number of generations. The morphological and biological characteristics of P. corni populations show geographical variation and also variation within the same region, depending on host plants. The existence of a number of different populations within P. corni is apparently determined primarily by the presence of the mainly bisexual population and several differing parthenogenetic clones.

In Chionaspis salicis (L.) and Phenacoccus aceris (Signoret), polymorphism does not depend on host plants, but shows geographical variation.

The species Lepidosaphes ulrni (L.), Aspidiotus nerii Bouch6 and Hemiberlesia cyanophylli (Signoret) have bisexual and obligate parthenogenetic forms which are morphologically similar. Coccus hesperidum L., Saissetia coffeae (Walker), P. corni and P. betulae have parthenogenetic and bisexual-parthenogenetic forms with different forms of parthenogenesis. (L)*

*L = lecture sessions; P = poster (market place) sessions.

Phytoparasitica 22:3, 1994 233

The Possible Evolution of the Plate-Like Structures Associated with the Anal Area of the Lecanoid Coccoidea

Chris J. Hodgson Dept. of Biological Sciences, Wye College

(University of London), Ashford, Kent TN25 5AH, UK

Some early workers, such as Green, postulated that the anal plates of the Coccidae were developed from anal lobes. Data were presented which strongly support this view, using examples from the family Coccidae and from the new eriococcid tribe Eriochitonini. In addition, the fate of the anal lobes in other lecanoid families was discussed along with the origin of the other plate-like structures found associated with the anal area in these families. It is concluded that the anal plates in the Coccidae and Eriochitonini are examples of convergent evolution and that, with the possible exception of the Aclerdidae, the sclerotized plate-like structures found in the other families have developed in a different manner. (L)

A Key to the Families of the Coccinea, Based on Characters of the Adult Male

Jan H. Gi l iomee Dept. of Entomology and Nematology, University of

Stellenbosch, 7600 SteUenbosch, South Africa

An attempt was made to construct a key to the families of the Coccinea, based on characters of the adult male. In addition to the taxonomic value of this key, it would be a useful aid in identifying scale insect males, trapped on pheromone and sticky traps, which are increasingly used in monitoring and controlling insect pests. (L)

Ultrastructure and Morphometric Analysis of the Wax Glands in Pit Scales (Homoptera: Coccoidea)

Imr6 Foldi I and Paris L. Lambdin 2 I Entomologie, Musdum National d'Histoire Naturelle, 75005 Paris, France; and

2Dept. of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37901, USA

Pit scales are enclosed in a protective waxy test constructed from secretions produced by a well-developed wax gland system. TEM/SEM and computerized images of these glands were assessed for the type species, Asterodiaspis variolosa (Asterolecaniidae), and for Cerococcus quercus (Cerococcidae) and Lecanodiaspis sardoa (Lecanodiaspididae), and their cuticular structures were then compared with 142, 55 and 63 species of these families, respectively, to evaluate relationships among pit scale insects.

Differences in the cytological characteristics in tubular duct wax glands of A. variolosa, C. quercus and L. sardoa include variations in the organites and the secretory vesicles. Differences in the cuticular features of this gland include shape and size of the outer and inner ductule, and the inner end of the outer ductule which is with or without cuticular projections.

The 8-shaped wax gland is formed of a central cell surrounded by four lateral cells and an intermediate cell. The gland produces two solid filaments that may be straight and parallel, or curled and divergent. Variations in gland structure, pore morphology and distribution may be used

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to distinguish between species. Of 23 dorsal 8-shaped pore patterns observed, the dominant arrangements were marginal rows with others evenly spaced in Asterolecaniidae (42.8%), swirl- like in Cerococcidae (43.6%), and a marginal band with others evenly spaced in Lecanodiaspididae (47.6%).

The multilocular disc-pore gland is composed of 8-12 cells arranged in a single, circular layer, with each cell opening into a common reservoir. The cells possess a smooth endoplasmic reticulum, numerous mitochondria, but no microviUi. A molding apparatus in the loculi defines the shape of the secreted wax. A basal layer of modified cuticle isolates this gland from the exterior, but allows for passive transfer of secretions.

Quinquelocular pore glands are present in all species in varying numbers at the base of the antennae, along the margin, in submarginal rows or along the spiracular furrows.

Cribriform plates occur in 98% of the described species of Cerococcidae and Lecanodiaspididae, but are absent in the Asterolecaniidae. Although the type of plate is consistent within species taxa, several variations occur in their arrangement.

Consistent cytological differences were noted in tubular duct and 8-shaped glands, but not in multilocular disc-pore glands. The highly modified Astero-type tubular duct distinguishes the asterolecaniids from the cerococcid-lecanodiaspidid lineage. The Cerococcidae differ from the Lecanodiaspididae by the number of teeth in the inner end of the outer ductule and by the narrower terminal knob on the inner ductule. A basic organization of 8-shaped pores is present; however, specific cuticular variations characterize familial taxa. These data infer a relationship between Asterolecaniidae and Cerococcidae taxa, but the diversity of types in Cerococcidae signifies a divergent evolutionary trend. Also, the absence of cribriform plates in Asterolecaniidae and their consistent presence in the cerococcid-lecanodiaspidid lineage is considered a characteristic feature. Our ultrastructural and morphometric study confirmed the monophyly of these three families. (L)

Variability of Morphological Characters and Its Use in the Systematics of Mealybugs (Pseudococcidae)

Salvatore Marotta and Antonio Tranfaglia Dip. di Biologia, Difesa e Biotecnologie Agro-Forestali,

Universitd della Basilicata, 85100 Potenza, Italy

Intraspecific variations in morphological characters are common in the taxonomy of mealybugs (Homoptera: Coccoidea: Pseudococcidae). Their incorrect or superficial interpretation has often led to the proliferation of synonymous nominal species or to undervaluation of the possible existence of cryptic or sibling species.

We have observed intraspecific variation in three species of Puto Signoret, namely, P. superbus (Leonardi) and P. taut&us (Borchsenius) in one case, and P. piloseUae (Sulc) in another o n e .

Puto superbus is a giant mealybug, distributed in the Mediterranean region and Central Europe. The adult females differ from those of P. tauricus only by the absence of dorsal tubular ducts on or near the cerarian plates. Both species have been collected at several localities in Central and Southern Italy, occupying the same niche in four collecting sites. At one locality, near Potenza (southern Italy), these species were systematically collected from 1989 to 1993, being found on the same host plant, and attaining the same developmental stage. A reliable taxonomic discrimination between these species was possible only after a study of microscope slides of the adult females. Among 315 specimens examined we found that the number of dorsal tubular ducts varied from 0 to 38. Only 26% of the specimens possessed more than 18 dorsal ducts, which is considered the lower range of this character in P. tauricus.


These findings would suggest that the use of morphological characters only is not sufficiently reliable for discrimination between P. superbus and P. tauricus, and further biological studies are required to assess their effective degree of evolutionary divergence.

Puto pilosellae is a polyphagous mealybug, widely distributed in the Palearctic region. The presence of a single circulus on the fourth abdominal segment of the adult female is generally regarded, in available taxonomic' redescriptions, as characteristic of this species. However, we studied 34 female specimens of this species from southern Italy, and found that a second circulus was present in two specimens. The second circulus is circular, very small, and situated on the fifth abdominal segment. The occurrence and number of circuli, and their use as a fundamental taxonomic character, were critically discussed. (L)

The Structure of the Spiracle in the Family Coccidae

Chris J. Hodgson Dept. of Biological Sciences, Wye College

(University of London), Ashford, Kent, TN25 5AH, UK

The structure of the spiracular opening of the soft-scale family Coccidae as seen with the scanning electron microscope, is rather different from its appearance as suggested when using cleared, stained, mounted specimens under the light microscope. We described the basic structure of the spiracle of soft-scales and explained this difference in appearance. It was concluded that there is little variation in spiracular structure in most subfamilies of soft-scales. However, within the new subfamily Myzolecaniinae, the structure of the spiracles is much more variable and some of this diversity was briefly described. It appears that this variation may be associated with their way of life. (L)

Antennai SensUla of Male Diaspididae (Homoptera: Coccoidea): Structure, Ultrastructure and Functional Interpretation

Francesco Porcelli 1st. di Entomologia Agraria, Universitd degli Studi, 70126 Bari, Italy

Data are given on the structure and ultrastructure of the antennae of some male Diaspididae using light microscopy, SEM and TEM. Further data are given, which are based on the use of methylene blue, crystal violet and simple axonal cobalt filling.

On the basis of this study, several kinds of sensilla were observed: mechanoreceptors (one campaniform sensillum, some mechanoreceptive setae and Johnston's organ) on the scapus and pedicellum, and chernosensory sensilla MPG and MPP (Zacharuk, 1985) and swWP (Altner & Prillinger, 1980) on the flagellomeres. Under light microscopy the MPG sensilla appear as sensiUa trichoidea while the MPP look like sensilla chaetica. Some 'knobbed setae', found on the last flagellomere, have a shaft similar to a MPG sensfllum; the proximal calyx of the apical knob bears a thick distal cutieular end with a cribrous aspect.

Based on comparative observations, it is hypothesized that the general organization of the sense organs is common to all the Diaspididae.

Systematic use of these data was attempted. (L)

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Studies of the Morphology and Taxonomy of the Males of Beesoniidae

Hu Xingping and Li Shizhu Dept. of Forestry, Shandong Agricultural University, Taian, Shandong, China

Sexual dimorphism is reported for the first time in species of Beesonia (Beesoniidae), occurring on plants of the Fagaceae. Beesonia brevipes Takagi is shown to be a junior synonym of B. napiformis Kuwana, since the former has been described from the male form of the first-instar larvae. All the instars of the male of B. napiformis are described and illustrated based on collections taken in China. Morphological differentiation of the sexes develops at the beginning of hatch of the first instars. The males develop through first instar, second instal prepupa, pupa followed by the adult male. All the stages of B. dipterocarpi (occurring on Dipterocarpaceae) are compared with B. napiformis and re-interpreted. The adult male of Beesonia is compared with Mangalorea, the only genera of the Bcesoniidae. The concept of the family is discussed. (L)

Revision of the Tribe Serrolecaniini Shinji (Pseudococcidae) with Discussion on Other Legless Mealybugs

Harlan Judson Hendricks Dept. of Biology, Bethel College, McKenzie, TN 38201, USA

Of the estimated 1100 species of mealybugs, approximately 6% are described as possessing degenerative legs and antennae in the adult female developmental stage or having lost these structures altogether. Fifteen genera comprising 63 species are often separated into their own taxonomic group based on these vestigial features (e.g. Sphaerococcinae), and known collectively as the 'legless' mealybugs. A comparative morphological analysis of adult females was undertaken to clarify the taxonomic placement of these species and to determine their relationships. Methods were included on collecting, preserving, slide-mounting, and measuring specimens, and on preparing illustrations. Keys to genera and species of 'legless' mealybugs were developed.

Reduction or loss of legs and antennae apparently occurred convergently in response to similar environmental conditions and was not found supportive of homogeneity in the 'legless' group as a whole. However, the genera Chaetococcus Maskell, ldiococcus Takabashi & Kanda, Kermicus Newstead, Serrolecanium Shinji, Tangicoccus Koz~r & Walter, and a new genus share many characteristics and were treated as the tribe Serrolecaniini Shinji. The aduk females of 13 species contained in these genera were redescribed, with illustrations produced for 12. A phylogenetic analysis of the tribe showed that converse to simplification in appendages, adaptations in other features (e.g. latero-projecting lobes and a caudally-directed vulva) probably developed to increase reproductive success and survival.

The genera Acinicoccus Williams, Antonina Signoret, Antoninoides Ferris, Cypericoccus Williams, Nesticoccus Tang, Paludicoccus Ferris, Parapaludicoccus Mamet, Peridiococcus Williams, Pseudantonina Green, and Sphaerococcus Maskell are not closely related to one another or to members of the tribe Serrolecaniini based on adult female morphology. These ten genera and their type species were redescribed, and illustrations produced for all but Nesticoccus sinensis Tang. Comments or redescriptions were provided for the 21 additional species that comprise these genera; however, the taxonomic placement of 18 additional species erroneously assigned to Pseudantonina and Sphaerococcus is uncertain.

Lectotypes were designated for Antonina crawi Cockerell, A. graminis Parrott, A. phragmitis Marchal, A. purpurea Signoret, A. waterstoni Newstead, ldiococcus bambusae Takahashi &


Kanda, Pseudantonina bambusae Green, Pseudolecanium disticlium Kuwana, and Sphaerococcus ethelae Fuller. A replacement name is proposed for the junior homonym Antoninella Sule. The species names Antonina anceps Green, Antonina maritima Green, and Idiococcus maanshanensis Tang & Wu are considered junior synonyms. Two species of Serrolecanium and a new genus were described. Six new name combinations were also made. (L)

Biology and Systematics of the Australian Genus Lachnodius Maskell (Eriococcidae) ~

John W. Beardsley Dept. of Entomology, University of Hawaii, Honolulu, HI 96822, USA

The genus Lachnodius was proposed by Maskell in 1896 to include Dactylopius eucalypti Maskell, described in 1892, and two additional new species. He did not speculate on taxonomic affinities. Subsequent authors have placed this genus with the Eriococcidae, the Pseudococcidae, or as a separate family level taxon. Evidence is presented to support placement of Lachnodius and closely related Sphaerococcopsis Cockerell as a subfamily, the Lachnodiinae, within the Edococcida~ (sens. lat.). Twenty-three Lachnodius species are known at present, 19 of which are described as new in a revision now in press. All species apparently feed only on trees of the genus Eucalyptus. Several typos of feeding sites are utilized: leaf pit galls (four species), open top or globular twigs (one species confirmed, five others probable). Most species exhibit hypermetamorphic development. Second-instar females have reduced, nonfunctional legs, followed by adults (third instar) with fully developed legs; these migrate away from feeding sites before forming ovisacs. In two species adult females have reduced, nonfunctional legs and are presumed not to migrate. Males of L. eucalypti (one of two species for which males are known) develop in leaf pit galls similar to, but smaller than those of females. Second-instar males have fully developed legs and when fully fed vacate their galls and migrate to secluded sites where pupal cocoons are formed. Most Lachnodius species known from more than one collection locality have been taken on more than one species of Eucalyptus, indicating that most probably they are not confined to a single host species. Many Lachnodius specimens are parasitized by wasps of the family Encyrtidae. As many as 24 specimens of a ?Metaphycus sp. emerged from large individuals ofL. lectularius collected in Victoria, Australia, in 1972. Parasitized specimens sometimes exhibit teratological changes in taxonomically useful structures, such as tubular ducts, making identification difficult. Most of the presently known Lachnodius species were collected in southeastern Australia. More field work, particularly in the western and northern parts of the continent, is likely to uncover many additional new species. (L)

~ not presented at the Symposium.

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The Biology and Relationships of the Eriococcid Genus Eriochiton Maskell

Rosa Henderson I and Chris J. Hodgson 2 ILandcare Research, Private Bag 92170, Auckland, New Zealand;

and 2Dept. of Biological Sciences, Wye College (University of London), Ashford, Kent, TN25 5AH, UK

Despite the presence of a pair of well-developed anal plates over the anal ring, the genus Eriochiton Maskell was considered to be a true member of the Eriococcidae and was transferred to this family by Hodgson (in press) based on characters of the adult female. Hodgson also raised a new tribe, the Eriochitonini, to take Eriochiton and a new genus, Neoeriochiton. Data are presented on the morphology of the adult male of Eriochiton, supporting its transfer to the Eriococcidae and comparing it with the structure of adult males from some other lecaniine coccoid families.

The Eriochitonini appear to be restricted entirely to New Zealand and currently are believed to contain two genera and six to eight species, each species apparently restricted to a fairly narrow range of host trees. The three species for which data are available appear to be univoltine. Adult females tend to be found on the stems, often associated with a strong preference for node sites, but the nymphs are found mainly on the leaves, on which the male prepupa and pupa also develop. Males are typically found in the spring and develop beneath a white test which has segmental lines. This tribe also differs from New Zealand Coccidae by the absence of a posterior hinged plate. The adult male develops within a felted test; the long, white wax, caudal filaments are the last structure to develop and, when fully extended, protrude posteriorly from the test. The male emerges backwards and is covered in powdery wax, giving an overall gray appearance. Initially it grooms this wax off the antennae using its forelegs. When it is walking about, it holds the tip of the abdomen curved up to keep the wax filaments off the substrate. Flight seems to be short and fast, possibly beginning with a leap. The females are viviparous; they appear not to move once they have settled. Each reproducing female harbors several nymphs beneath its abdomen. It is the adult female which overwinters. Infestation sites are accompanied by much sooty mold. (P)

A Revis ion of the Genus Micrococcus L e o n a r d i wi th an Analys i s of I t s F a m i l y Placement

Douglass R. Mil ler 1 and Douglas J. Wi l l i ams 2 1Systematic Entomology Laboratory, USDA, Beltsville,

MD 20705, USA; and 2Natural History Museum, London, SW7 5BD, UK

The genus Micrococcus Leonardi encompasses seven species, all of which are Mediterranean in distribution. Species in the genus have three instars in the female and probably five in the male. Until now the genus was regarded as a member of the Eriococcidae; however, its placement into a family is problematic since (i) the adult female possesses bilocular pores and ducts, invaginated tubular ducts, and lobes that are modified into anal plates, and (ii) the adult male possesses an unsclerotized aedeagus tip. An analysis was made of the relationships of the genus with other genera of scale insects.

We have studied a single unusual specimen of Micrococcus silvestrii I.e, onardi, that possessed male genitalia and many other male characteristics and also an anal ring and a well developed labium. This specimen is believed to be a gynandromorph. (L)


Morphology of Nymphs and Biology of Rhodococcus perornatus (Cockerell & Parrott) (Coccidae) in Hungary

Gizela OrdSgh Dept. of Entomology, University of Horticulture and

Food Industry, H-1502 Budapest, Hungary

Rhodococcus perornatus (CockereU & Parrott) was formerly known as a rare, steppe- inhabiting, mesophilous species. However, in recent years it is becoming a pest of cultivated roses in Hungary, mainly in the Budapest area. It develops one annual generation. In the unusually dry and hot spring of 1993, all the eggs hatched in Buda by mid-June. All nymphs settled on the twigs by the end of June. The average number of eggs per female is 265. This soft scale overwinters as a second-instar nymph.

The nymphs have been described and illustrated. (L)

W h a t are the Correc t Taxonomic Charac te r s of the Type Species of Matsucoccus Cockerell (Margarodidae)? ~

Tang Fang-Teh Entomological Institute, Shanxi Agricultural

University, Shanxi, Taigu County 030801, China

The genus Matsucoccus Cockerell (Homoptera: Margarodidae) was established for the type species Xylococcus matsumurae Kuwana. Taxonomic redescriptions of the type species were published by several authors, but there are reasons to suggest that the real features of the former are not correctly interpreted. (i) The type series of Kuwana was destroyed by a 1923 earthquake in Japan (Sadao Takagi, personal communication). (ii) Until recently, M. matsumurae was supposed to be the single species of the genus, occurring in Japan. However, Miller and Park (1987) described M. thunbergianae from Korea, and it occurs also in Japan.

Since the type series of M. matsumurae was lost, its correct taxonomic characters need to be established, considering the fact that at least two species of the genus are present in Japan. (L)

Species Identification with RAPD-PCR: A Determination Key for Six Species of the Genus Quadraspidiotus

MacGillivray (Diaspididae)

Jfirg E. Frey and Beatrice Frey Federal Research Station, CH-8820 Wiidenswil, Switzerland

The genus Quadraspidiotus MacGillivray (Homoptera: Diaspididae) is represented in Switzerland by eight species. One of them, Q. perniciosus (Comstock), is a quarantine pest in Switzerland and its occurrence is monitored by pheromone-treated sticky traps, on which only winged males of the scale insect are captured. Until now, no determination key based on morphological characters has been published for the adult male; it was therefore impossible to determine the degree of species specificity of these pheromone traps in Switzerland.


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Based on RAPD-PCR (random amplified polymorphic DNA - polymerase chain reaction), we established a molecular determination key for six Quadraspidiotus species. Four of the species are orchard pests: the three native species - Q. pyri, Q. marani, Q. ostraeformis - and Q. perniciosus, which is not native to Switzerland. Two additional species we analyzed are Q. gigas living mainly on poplar and willow, and Q. zonatus developing mainly on oaks and beech.

Our molecular determination key is robust: no purification of the DNA prior to analysis is required; and it is highly reproducible, as the same patterns were found in individuals from populations as far as 3000 km apart. Moreover, this technique can be used for both sexes and the developmental stages. Using this method it is possible to identify the species of the trapped adult males, and establish reliable data on the occurrence and distribution of an important quarantine pest. (P)

B: ZOOGEOGRAPflY AND FAUNISTICS

New Data on the Zoogeography of Palearctic Coccoidea (Homoptera)

Ferenc Koz,ftr Plant Protection Institute, Hungarian

Academy of Sciences, H-1525 Budapest, Hungary

The large-scale zoogeographical affinities of the distribution pattern of Coccoidea of the Palearctic region, and subregions, were studied by Koz,qr and Drozdjak (1987), based on the species richness of all Coccoidea families. Here we analyze this question concerning the number of local genera, which are used for the characterization of different levels of zoogeographical units.

The analyses are based on Kozgr and Waiter's (1985) check-list, which contains 1938 species in 391 genera in 19 families. The Palearctic region comprises 391 genera (F. KozAr, Catalogue Palearctic of Coccoidea, in preparation), of which 101 are cosmopolitan, and 100 distributed in several subregions. The numbers of 'local' genera, to the best of our present knowledge, are: Euro- Siberian - 17, Irano-Turanian - 24, Mediterranean - 51, and Far Eastern - 98. This means that almost half of the genera (48.6%) are local ones and most of them are monotypic, which shows that the region and the subregion have an old, well differentiated endemicity on the generic level. A further analysis concerning genera distributed in two subregions, shows that the number of joint genera ranges from 5 to 15. The highest number of common genera was between Mediterranean and Irano-Turanian subregions, which demonstrates a phylogenetic similarity of these subregions. In this case the number of common genera in the Euro-Siberian subregions is equal to that of all other subregions. A wider analysis, including all genera and species, shows that the Euro-Siberian and Irano-Turanian subregions have a greater similarity, which reflects a similar trend of speciation, endemicity on species level, and a stronger connection by species migration routes. The Far East has a very rich and in every respect highly differentiated fauna. The specific endemicity could be studied in more det~l in subregions, or even in different districts of subregions, as was "lone for the Levant region by Ben-Dov (1990) on Pseudococcidae.

Analyzing the affinities of the distribution of different families between subregions, we could find different connections. In Coccidae, the Euro-Siberian and Mediterranean subregions have a high number of local genera, but by common genera the Euro-Siberian subregion is connected with the Irano-Turanian also. In the ease of Diaspididae and Pseudococcidae, we found larger numbers in Mediterranean and Irano-Turanian subregions, but by common genera we found a strong connection only in the Diaspididae family. The Far Eastern subregion has marked differences, especially in the Diaspididae and Pseudococcidae families. (L)


Coccinea of Northeastern North America

Michael Kosztaxab and Mary Rhoades Dept. of Entomology, Virginia Polytechnic Institute

and State University, Blacksburg, VA 24061-0319, USA

An assessment by U.S. homopterists in 1990 found that approximately 324 species, or 27% of all Coocinea species, have not been described as yet from North America. In addition, for all Coccinea" most of the immature stages and adult males remain undescribed, and updated information on biology and distribution is lacking. The reason for the dismal current status is that available identification manuals for most of the families are 40 to 65 years old. To improve the situation, we initiated work on a book for identification of Coccinea occurring in North America. The manual will include the scale insects from 19 States and the District of Columbia, in the U.S.A. north of the southern borders of Kentucky and Virginia (36030 ' N latitude), and east of the rivers of Mississippi and St. Croix. In Canada the region includes the six provinces (and some islands) east of the border of Manitoba (95 ~ W longitude), as far north as Ellesmere Island. Excluding greenhouses, we know to date from this area approximately 217 species belonging in 84 genera and 13 families. Only a few examples of endemism were found. Most species have a wide distribution in North America, including many polyphagous pest species.

Utilizing the accumulated data from our files over the past 33 years, and other sources dealing with scale insects in this region, we have compiled and updated information on each species. Included in the book will be keys, illustrated morphological descriptions, an extensive list of references, and information on distribution, hosts, biology/life cycle, natural enemies, other associated organisms, and economic importance.

The manual will be designated the fourth contribution to a U.S. National Biological Survey, and it is hoped that it will provide a stimulus for colleagues in the southern and western U.S.A. to prepare comprehensive identification manuals for those regions. (L)

Diaspidoid Fauna of South Asia ~

R.K. Varshne Zoological Survey of lndia, New Alipur, Calcutta 700053, India

A check-list of the scale insects and mealybugs of South Asia, in two parts, has been compiled. It consists not only of a check-list of various names applied to different taxa, but also the known records of host-plants and the localities of occurrence in the eight countries of South Asia, namely, India, Pakistan, Nepal, Bhutan, Bangladesh, Myanmar, Sfi Lanka and Maldives. Part I of the check-list, dealing with 15 families, 117 genera and 341 species and subspecies, was published by Varshne in 1992. Part 11 of the check-list, dealing with Diaspidoid scales, is in manuscript stage and will include the following taxa:


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Family-Group No. of No. of category genera species

Superfamily DIASPIDOIDEA Family HALIMOCOCCIDAE 1 1 Family DIASPIDIDAE

Subfamily PROTODIASPIDINAE 1 1 Subfamily PARLATORIINAE

Tribe KUWANAPIDINI 1 3 Tribe LEUCASPIDINI 5 11 Tribe PARLATORIINI 14 54

Subfamily ODONASPIDINAE Tribe RUGASPIDIOTINI 2 2 Tribe ODONASPIDINI 4 10

Subfamily ASPIDIOTINAE Tribe ASPIDIOTINI 31 90

Subfamily DIASPIDINAE Tribe LEPIDOSAPHEDINI 21 54 Tribe DIASPIDINI 32 136

Total 112 362

As Part II of the check-list will be the final one, Addenda et Corrigenda to Part I will be included in it. (L)

Scale Insects (Homoptera: Coccoidea) of Coniferous Plants in the Parks of Russia ~

Elga Kozarzhevskaya Main Botanical Garden, Russian Academy of Sciences, Moscow 127126, Russia

About 150 species of scale insects are known to develop on coniferous trees in different countries of the world. A number of coccids attack ornamental conifers in urban conditions throughout Russia.

The fauna of the spruces is represented by two common species: Physokermes hemicryphus and Ph. piceae; the first is widespread and occurs in rather large numbers, whereas the second is not so common.

Nuculaspis abietis is very common on pines. Towards the south pines are attacked by some other species, such as Leucaspis loewi, L. pusiUa and Lepidosaphes newsteadi.

Thuja trees are attacked by the common coccid Parthenolecanium fletcheri and in southern regions by Carulaspis carueli, C. juniperi and Lepidosaphes juniperi. The last mentioned species may cause damage to Juniperus, Biota, Cupressus and Chamaecyparis. The yew scale, Parthenolecanium pomeranicum, feeds on Taxus spp.

Two species of mealybugs infest ornamental coniferous trees: Phenacoccus piceae on spruce and Planococcus vovae on Juniperus; both are sometimes serious pests. The species Phenacoccus maritimus has been recorded in parks of the Far East regions.

The most abundant coccid fauna is on green plantings along streets, local ornamental plantings, ornamental nurseries and less so in parks.



Coccids cause various types of damage, including discoloration, premature needle fall, reduction of shoot growth, death of branchlets and branches and even of the whole tree. Sooty mold fungi develop on honeydew excretions and blacken the tree. Under urban conditions trees often may be weakened by several factors, such as activities of man, attacks by eoccids, or pathogens. The symptoms of injury may be similar. Trees under stress from smog, soil moisture deficit, soil compaction, root damage or other causes tend to be especially susceptible to coccid attack. Trees along dusty roads often have a higher rate of infestation than those farther from such roads. This may be due to the deleterious effect of pollution on the natural enemies of scale insects, and reduced photosynthesis, which may favor scale survival. (L)

A List of the Italian Homoptera Coccoidea

Santi Longo,l Salvatore Marotta, 2 Giuseppina Pellizzari, 3 Agatino Russo I and Antonio Tranfaglia 2

list. di Entomologia Agraria, Universitd di Catania, 95129 Catania; 2Diff. di Biologia, Difesa e Biotecnologie Agro-Forestali, 85100 Potenza; and

~Ist. di Entomologia Agraria, Universitd di Padova, 35131 Padova, Italy

A list of the scale insects (Homoptera: Coccoidea) recorded from Italy is given. This list is based on data collected by the authors and on bibliographic sources. In all, 342 species of scale insects belonging to 14 families are known today in Italy. The most numerous families are Pseudococcidae (113 species), Diaspididae (114 species), Coccidae (50 species) and Eriococcidae (23 species). The Margarodidae and Asterolecaniidae each have 10 species; the remaining families (Ortheziidae, Kermesidae, Cryptococcidae, Micrococcidae, Cerococcidae, Aclerdidae, Lecanodiaspididae, Phenicococcidae) have a lower number of species (from 7 to 1).

The distribution of each species in the Italian territory is shown in the list by marks that indicate whether the species is present in northern Italian regions (N), in central and southern Italy (S), in Sicily (Si), or in Sardinia (Sa). Species known to live only in greenhouses are marked with an asterisk. Many scale insect species, some of which are widely distributed in Italy, are exotic, acclimatized species. The year of incidental introduction into Italy and the origin of these species are reported.

The authors consider this list a starting point for further investigation. In fact, in spite of an increase in faunistic research carried out in Italy during the last two decades, the Italian fauna of Homoptera Coccoidea is not yet satisfactorily known. Many Palaearctic species, belonging mainly to Pseudococcidae, and Eriococcidae are expected to be present in Italy also and several undescribed species are deposited in the authors' collections. In addition, incidental introductions of exotic species are becoming a quite common event. For the above mentioned reasons, the number of scale insect species in Italy will surely increase in the future.

This work was supported by the Italian Ministry of Environment as part of a major project devoted to the composition of the Italian fauna. (L)

244 Meetings

Scale Insects Recorded from Import Interceptions and in Greenhouses in the Netherlands

Maurice Jansen Section Entomology, Plantenziektenkundige Dienst,

6700 Wageningen, the Netherlands

A list is given of the species of Coccoidea which have been intercepted on plants imported into the Netherlands during the last few decades. Data are provided on host plants on which the coccoids were intercepted, and their country of origin. A survey was carried out to confirm which species became established in greenhouses, and information is given on several cases. (L)

Ethnococcidology: Use of the Giant Margarodids, Llaveia spp. (Margarodidae), by Indigenous Peoples of Mesoamerica in Their Culture, Medicine and Arts

Michael L. WiUiams I and Charles M. MacVean 2 I Dept. of Entomology, Auburn University, Auburn, AL 36849-5413, USA; and

linst, de Investigationes, Universidad del Valle, (M-187) Guatemala City, Guatemala

Extracts from giant margarodids in the genus Llaveia (Signoret) (Coccoidea: Margarodidae) have been used for centuries by the indigenous peoples of mesoamerica as waterproofing agents, medicines, and as a base for lacquer work. Since the early sixteenth century, Mayan Indians have used a wax from L. axin (Llave) as a preservative and pigment base on carved, painted limestone buildings and for decorated lintels on these buildings that were made of zapote wood. The wax of a closely related species, L. mexicanorum (CockereU), is used to the present day as a finish and preservative for cups and bowls made from gourds that are sold in villages throughout Guatemala. This natural wax is of particular interest because it has been used on eating utensils for centuries, and its widespread usage provides considerable evidence that there are no toxic or undesirable effects associated with the wax.

The product used is not a wax, but is actually the fat of the insect which is extracted by a laborious process involving collecting the insects, called 'nij', washing the powdery wax from their bodies, cooking them, mashing out the body contents, rinsing, straining, and then churning the resulting solution to separate the fat before storing it in solid form as a loaf or ball of 'aje'. Pure 'aje' is then used as a waterproofing and polishing agent for articles of wood or pottery, as a base for face and body paints, and artistically for binding pigments used in decorating wooden artifacts. In folk medicine the 'aje', or body contents of the insect itself, is used for external wounds, swelling and skin afflictions as a medicinal unguent.

Representatives of the genus Llaveia have been recorded from Mexico down through Central America, and in Ecuador and Peru in northern South America. Five species are currently assigned to the genus, namely axin (Llave), bouvardi (Signoret), mexicanorum (Cockerell), oaxacoensis Morrison, and uhleri (Signoret), but much confusion exists in the taxonomy of the group.

Recent expeditious by the authors into areas where 'aje' production and use once flourished, indicate that this ancient practice may be vanishing because of a lack of knowledge about its production and use, and replacement in the arts by synthetic materials. (L)


C: BIOLOGY, MONITORING AND ENVIRONMENTAL IMPACT

Study of Further Spread ofPseudaulacaspis pentagona (Targioni-Tozzetti) (Diaspididae) in Central Europe

Diaa A.F. Sheble and Ferenc Koz,~r Plant Protection Institute, Hungarian Academy of Sciences,

H-1525 Budapest, Hungary

A northward expansion of the white peach scale, Pseudaulacaspis pentagona (Targioni- Tozzetti), occurred in Hungary during the last 20 years (Koz~, 1991). The spread was accelerated by mild winters during this period. In this study we surveyed the pest by visual monitoring on its preferred host plants, such as Morus, Sophora and Syringa. The survey included 98 sites in Austria, Bulgaria, Hungary, Romania and Slovakia during the years 1990-1992. In the places where no infestation was found by the visual method, we used pheromone traps (the component was kindly provided by Dr. B. Kovalev (Kishinev, Moldavia) and Dr. J.H. Tumlinson (Florida, USA). The traps used were Hungarian tent traps (10xl0 cm) incorporating "l'anglefoot', which were placed at 27 sites on Sophora trees, during the second flight period of the males.

By the visual survey we found 50 sites infested with this pest, at a density which was usually very high (3-4 on a scale of 0 to 4), whereas 48 sites were free of the pest. However, using pheromone traps we found that 11 of the latter sites were also infested, although the other sites were judged free of pests also by this method. In a repeated visual survey at these 11 sites we found infestation in only two. The four sites outside of Hungary were free of infestation. In 1992 we found that the pest was present at two sites, which had been free in 1991 according to the traps. At the sites where infestation could be detected only by traps, we collected 42-973 males for one flight period, while at a heavily infested site one trap collected 12,275 males.

The results show that this pest can be surveyed efficiently by the visual method, while the pheromone traps are helpful in uncovering low infestation. The spread of this insect in Central Europe continues. It is important to follow the process of distribution by pheromone traps in additional countries in Europe. This species, as a thermophilous insect, could serve as a good indicator in a study of the effect of possible global wanning on the distribution of insects. (L)

Bio-Ethologicai Observations on Phenacoccus madeirensis Green (Pseudococcidae) in Sicily

Angela Sinacori Ist. di Entomologia Agraria, Universitd di Palermo, 90128 Palermo, Italy

The mealybug Phenacoccus madeirensis Green was first recorded in Sicily, Italy, in 1991, where it was found on Erythrina sp. and on Acanthus sp. Our studies of this mealybug in Sicily have confirmed that it reproduces parthenogenetically, and develops four generations a year. The mealybug overwinters as an egg or first-instar nymph, settled along leaf ribs. The duration of the different stages at 30~ is: egg, 4-5 days; 1st instar, 2-4 days; 2nd instar, 6-8 days; 3rd instar, 6--8 days. (L)

246 Meetings

Monitoring Populations of the Maritime Pine Scale, Matsucoccus feytaudi Ducasse (Margarodidae), Using Sex Pheromone Traps:

A Preliminary Study ~

Hervd Jactel,l N. Perthuisot, l p. Menassieul and J. Einhorn 2 I Laboratoire d' Entomologie Forestidre, Station de Recherches

Forestidres, INRA, 33611 Cestas; and 2Station de Phytopharmacie, INRA, Route de Saint-Cyr, 78026 Versailles, France

The Maritime pine scale, Matsucoccus feytaudi Ducasse, is endemic in southwest France, where it causes considerable damage to pine. The pest is found within the largest forest in Europe (1.2 million ha), and requires an intensive survey effort. The recent identification of the chemical structure of its female sex pheromone has led to use of the pheromone in traps for estimation of the pest populations.

Sexual trapping of M. feytaudi was carried out in 1993 in four pure stands of Pinus pinaster Ait. in Aquitaine. Two of the stands consisted of 13-year-old pines (young) at a high plantation density (1300 trees/ha). The two other stands consisted of 20-year-old pines (middle-aged) at a moderate plantation density (750 trees/ha). Each stand was partitioned into four plots, each containing four pheromone traps. Traps were baited with (2E,4E)-4,6,10-trimethyl-2-4- dodecadien-7-one (the female sex pheromone of M.feytaudi) in two plots at a dose of 30 p.g and in the two other plots at 5 txg per trap. A systematic sampling was developed to estimate the number of larvae per tree. The method appeared to be efficient, precise and weakly biased. The correlation between the number of male M. feytaudi caught in the pheromone traps and the number of exuviae of seeond-instar larvae found in the support trees was examined.

The number of exuviae per tree was significantly correlated with the number of males caught on the same tree only for the 5 gg dose in middle-aged plantations. The number of exuviae per tree was significantly correlated with the average number of males caught in the same plot for only the 30 I.tg dose in middle-aged plantations. In young plantations, pheromone trap capture rates were high when the number of larvae was low and varied widely between trees.

The suitability of sexual trapping, as a monitoring method for M. feytaudi populations, therefore appears to depend on three parameters: first, the trapping attraction radius (pheromone dose-dependent); second, the ratio of exogenic/endogenic flying males; and third, the heterogeneity of the spatial distribution of the scale among trees. The latter two parameters are dependent on population level. (L)

The Role of Matsucoccusjosephi Bodenheimer & Harpaz (Margarodidae) and Drought in the Early Stages of Natural

Regeneration after Fire in Aleppo Pine Forests in Israel

Zvi Mendel, 1 Fabienne Assael, I David Nestel, 1 Nitza Saphir 2 and Amiram Zehavi 2 1Dept. of Entomology, ARO, Bet Dagan 50250; and 2Forests Department, Jewish National Fund, Eshta' o199775, Israel

The mortality of pine seedlings was studied during the early years of natural regeneration after Rre in a Pinus halepensis forest, with special emphasis on the role of Matsucoccus josephi and drought. The investigations were conducted in a natural forest on Mt. Carmel, erroneously



supposed to be resistant to the scale insect, and in a forest severely damaged by the scale at Horeshim in Samaria. M. josephi was the dominant mortality agent, with ca 44% of the seedlings being killed by the scale during the first 4 years after regeneration. No injury or mortality due to M. josephi was recorded during the first year after regeneration, with maximum mortality occurring during the third and fourth years. About 23% of the seedlings died due to drought, and interspecific and intraspecific competition, particularly during the first 2 years after regeneration. Mortality due to other biotic agents was practically nil. It was found that resistance to the scale of regenerated trees on Mt. Carmel does not differ significantly from that at Horeshim in spite of the difference in the level of injury to mature trees on each site. Seedling density in scale-infested plots, 4 years after seeding, is adequate to ensure stand development, with the second growth possibly displaying less susceptibility to M. josephi than the present trees. (L)

Populations of Rhizoecus sp. (Pseudococcidae) in Post-Fire Soil of a Pine Forest in the Carmel Nature Reserve, Israel

Meir Broza, 1 D. Poliakov, 1 S. Weber 1 and Yair Ben-Dov 2 1 University ofHaifa, Oranim, Tiv'on 36006; and 2Dept.

of Entomology, ARO, The Volcani Center, Bet Dagan 50250, Israel

In September 1989 a huge forest fire consumed a large portion of the natural Aleppo pine forest in the Carmel Nature Reserve, Israel. The soil microarthropods in both burnt and unburnt plots of the Reserve have been studied since 1991. Acari and Collembola comprised about 80% of the total number of arthropods found in standard soil samples, whereas the rest belonged to 18 other orders or classes of the Arthropoda. In November 1991, 2 years after the fire, a remarkable increase in the numbers of mealybugs (Coccoidea: Pseudococcidae) of a Rhizoecus sp. was recorded in the soil of the burnt area only: 286 mealybugs were collected from 12 soil cores (diameter 5 cm), which constituted 70% of the total arthropods, excluding Collembola and Acari, sampled; in the unburnt area, only 23 mealybugs were collected from similar cores. A sharp decline in mealybug numbers was recorded in February 1992, probably due to a one-week snowfall, which is extremely rare in this Mediterranean region. The relatively high number of mealybugs in the burnt area was recorded for about 15 months, after which the population diminished to a density similar to that in the unburnt plot. The Rhizoecus mealybugs were more abundant in soil samples taken close to the root system of sowbread, Cyclamen persica (Primulaceae). (P)

Effect of Urban Air Pollution on the Population of Eulecanium gigantea (Shinji) (Coccidae) in Taiyuan City, China ~

Xie Yingping, 1 Liu Xianqian, 1 Li Jingping 2 and Tang Min 2 1Dept. of Forestry, Shanxi Agr&ultural University, Taigu 030801; and

2Taiyuan City Environment Protection Science Research Institute, Taiyuan 030001, China

Scientists have paid great attention in recent years to biological monitoring of air pollution in the urban environment. Various districts in a city, such as industrial, traffic centers, residential and cultural, have different sources of air pollution, requiring therefore the corresponding organisms as pollution indicators. We conducted a study of changes in population density of Eulecanium


248 Meetings

gigantea (Shinji) (Homoptera: Coccidae) in Taiyuan City, China, where both this soft scale and its host plant, Sophora japonica, have been affected by air pollution.

The results were as follows: (i) Air pollution in the streets is caused by automotive exhaust gases (such as CO, NO x, SO2), lead, dust particles and some secondary polluting products (such as photochemical smog and sticky colloidal substances). (ii) The scale population density (SPD) is positively correlated with the number of cars (auto no.) driving in a certain district. The correlation coefficient is

o r

Y (SPD) = +15.67 + 0.003695X (auto no.)

Y (auto no.) = 643.96 + 22.9X (SPD) ; the correlation index r = 0.92**.

(iii) The scale population density varies from 230 per tree in the city center, to 10-30 per tree in suburban districts. (iv) The highest insect density was recorded in districts with the greatest number of vehicles, and the greatest dustiness of the air. Medium density was found in residential districts, and the lowest in the cultural and industrial districts. (v) The insect density was positively correlated with air pollutants, such as total suspended particles, fallout dust, CO, NOx and SO2.

It is concluded that the density of the scale insect population can be used for monitoring air pollution in city streets. (L)

Flight Monitoring of the San Jose Scale, Quadraspidiotus perniciosus (Comstock) (Diaspididae) and Its Parasitoid Encarsia perniciosi (Tower)

(Aphelinidae) in Northwest Switzerland

Carsten Hippe and E. Mani Swiss Federal Research Station for Fruit Growing,

Viticulture and Horticulture, C1t-8820 Wiidenswil, Switzerland

The flight of the San Jose scale, Quadraspidiotus perniciosus (Comstock) (Homoptera: Diaspididae), and its parasitoid Encarsia perniciosi (Tower) (Hymenoptera: Aphelinidae) was monitored in Northwest Switzerland during 3 years (1990-1992). The two isomers SJS-1, (Z-3,7- dimethyl-2,7-octadien-l-yl propanoate) and SJS-3, (E-3,7-dimethyl-2,7-octadien-l-yl propanoate) were tested for their attractiveness to adult males of the scale as well as to the parasitoid. Two main flight periods of the San Jose scale were recorded: the first occurred in May, while the second one lasted from mid-July to the end of September. E. perniciosi was captured in the pheromone traps from May until September, but numbers were higher at the beginning of the flight period of the scale. In direct comparisons, SJS-1 trapped more scale males than SJS-3, which, on the other hand, was more attractive to the parasitoid. Examples of the daily recorded catches of the San Jose scale were given, with special reference to the effect of evening temperature, wind speed and precipitation. (L)

Mealybugs as Vectors of Plant Viruses

Edna Tanne Dept. of Virology, ARO, The Volcani Center, Bet Dagan 50250, Israel

Eighteen species of mealybugs (Pseudococcidae), belonging to ten genera, have been reported to be vectors of plant viruses since the 1950s. First reports pointed out that the transmission of


tobacco mosaic virus from systemically infected tobacco plants to healthy tobacco, tomato and Nicotiana glutinosa plants initially considered to be stylet-borne, could be attributed to virus carried on the tarsi. Mealybugs appear to be the only vector of cacao viruses, which have a severe economic impact on the cacao crop. The transmission of cacao viruses, especially cacao swollen shoot virus by Planococcoides njalensis (Laing), which has been studied, appears to be circulative. In the late 1970s mealybugs were suspected to be vectors of the Dasheen mosaic virus in the South West Pacific.

Since the mid 1980s three additional species, discussed below, were proved to be vectors of grapevine leafroU disease and grapevine corky-bark disease. Pseudococcus longispinus (Targioni- Tozzetti), Planococcus ficus (Signoret) and to some extent Planococcus citri (Risso) proved to transmit different closterolike viruses associated with both diseases, from infected to healthy grapevines and in some cases to herbaceous plants. Transmission by mealybugs is so far the only evidence that these viruses are the causal agents of these diseases, as Koch's postulates have not yet been fulfilled.

Field surveys and control experiments in Israel demonstrated the spread of diseases in vineyards and the possible restriction of spread by mealybug control.

In 1993 Minafra and Hadidi detected grapevine virus A in mealybugs by immunocapture- reverse-transcription polymerase chain reaction, providing molecular proof for the acquisition and retention of this virus by P. longispinus. (L)

D: PtlENOLOGY AND POPULATION DYNAMICS OF COCCOID PESTS AND THEIR NATURAL ENEMIES

Life History and Seasonal Cycle of a Mango Scale Insect, Icerya zimmermani (Green) (Margarodidae), at Bhagalpur, India ~

Moil Lal Gupta and P.K. Sinha Dept. of Zoology, Bhagalpur University, Bhagalpur 812007, India

Several aspects of the biology of lcerya zimmermani (Green) (Homoptera: Margarodidae), a serious pest of mango in India, were studied at Bhagalpur, India. The white margarodid invariably settles along the midrib and veins on the undersurface of leaves. The female life cycle consists of three nymphal stages and the adult female, while the male has five stages: two nymphal, prepupa, pupa and adult. The female completes its life cycle in 70-139 days and the male in 37-61. The duration of development of the first nymph, second male nymph, second female nymph, prepupa, third female nymph and pupa is 12-19, 12-20, 23-43, 4-7, 12-31 and 7-12 days, respectively. The adult male lives for 1-3 days, and the adult female for 23--47 days. The species has four annual generations, viz. August to December, October to March, February to June, and June to mid-October. There is a considerable overlap between successive generations, and between the different instars of the same generation. During the 2-year study, minor variations were observed in the duration of generations, due to local weather variations. (L)


250 Meetings

Population Dynamics of the Mango Scale, Aulacaspis tubercularis Newstead (Diaspididae), in South Africa

Thomas I. Labuschagne I and H. Van Hamburg 2 l lnst. for Tropical and Subtropical Crops, Nelspruit 1200;

and :Dept. of Zoology, P otchef strooma University for Christian Higher Education, Potchefstroom 2520, South Africa

Ecological aspects in the life history of Aulacaspis tubercularis Newstead, such as population composition, population fluctuation, spatial distribution and natural enemies, were analyzed, using data gathered in two localities in South Africa, namely, Kaapmuiden (25029 ' 31024 , and Nelspruit (25027' 30~ On average, 350 females and 550 males were examined fortnightly during a period of 12 months, to determine the distribution of the developmental stages and the rate of parasitization. Eight leaves per tree, two in each quadrant, were randomly picked to determine the relative abundance and the spatial distribution of the scale within the tree; 20 randomly selected trees per orchard, were used for this purpose. The highest numbers of the mango scale occurred on the shady, south-facing, lower aspect of the tree. Population peaks of the mango scale occurred at different times in the two localities. The population peaks of the scale at Kaapmuiden, with a higher mean temperature, occurred in August, much earlier than at Nelspruit, where the peak was recorded in November. The generations overlapped to such an extent that no peaks in the developmental stages could be detected. The indigenous parasite, Aspidiotiphagus citrinus Craw, was incapable of controlling populations of the mango scale, despite the fact that the rate of parasitization exceeded 80% at certain periods of the year. (L)

Phenology of the Pyr i fo rm Scale, Protopulvinaria pyrO~ormis Cockerell (Coccidae), and Distribution of I ts Natura l Enemies in Israel

Dror Hadar, 1'2 Manes Wysoki I and David Rosen 2 I Dept. of Entomology, ARO, The Volcani Center, Bet Dagan 50250;

and 2Dept. of Entomology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot 76100, Israel

The pyriform scale, Protopulvinaria pyriformis Cockerell (Homoptera: Coccidae), has been an important pest of avocado in Israel since 1980. Avocado plantations in Israel are under effective biological control, and it was therefore important to find a solution to this problem which would not interfere with the existing biological equilibrium. The pyriform scale develops two generations annually on avocado: a winter generation peaking in November-December, and a summer generation peaking in June-July. Ovipositing females are not susceptible to spray oils, but in January and July-August the population consists of young stages, and during these periods light oils may be used for control. The reduced population then allows natural enemies to exert effective control.

Parasitoids of the pyriform scale have been introduced into Israel from South Africa, Kenya, Florida, California and Spain. Metaphycus swirskii Annecke and Mynhardt (Hymenoptera: Encyrtidae), initially the most abundant parasitoid, was soon replaced by Metaphycus stanleyi (Compere), a later introduction which has become the most abundant natural enemy. Metaphycus helvolus (Compere) has also become established on avocado, but to a lesser extent and is now quite rare. Two hyperparasitoids, Pachyneuron concolor (FiArster) (Hymenoptera: Pteromalidae) and Marietta javensis (Howard) (Hymenoptera: Aphelinidae), have an adverse effect on the


effectiveness of Metaphycus spp. In some groves, up to 70% of the total parasitoid fauna consists of these hyperparasitoids. The percentage of active primary parasitism increases in September, is high during winter, and peaks in May; it then declines in summer, due both to climatic factors and encapsulation.

Metaphycus spp. differ in the site, duration and rate of oviposition, in host marking, and in their preference for host stages. M. helvolus oviposits in body margins of the pyriform scale, whereas M. stanleyi oviposits through the host's dorsum. The duration of oviposition is short (7 sec) in M. stanleyi and relatively long (68 sec) inM. helvolus; the former lays 13 eggs per hour, the latter only 3. M. stan/eyi attacks only third-instar larvae and young females, whereas M. helvolus attacks also second instars, but may be repelled from ovipositing by the host's body movements. (P)

Observa t ions on the Biology of Some Scale Insects (Homoptera: Coccoidea) in Sicily, I ta ly

S. Longo, 1 G. Mazzeo 2 and Agatino Russo 2 llst. di Difesa delle Piante, Universitd degli Studi, 89061 Gallina (RC); and 21st. di Entomologia Agraria, Universitd degli Studi, 95123 Catania, Italy

Observations were presented on the biology and ethology of several species of scale insects that occur in Sicily, Italy. Special reference was made to the mealybugs (Pseudococcidae) Phenacoccus madeirensis Green, P. silvanae Longo & Russo, P. yerushalmi Ben-Dov (the last has been recently found in Sicily) and the soft scale insect (Coccidae) Scythia aethnensis Russo & Longo, (L)

Graminicolous Scale Insects of Turkmenistan

Svetlana N. Myartseva, G.A. Kalagina and A.G. Potaeva Inst. of Zoology, Academy of Sciences of Turkmenistan,

744000 Ashkhabad, Turkmenistan

Grasses constitute an important part of the flora in Turkmenistan mountains, river valleys, deserts and oases. So far, 25 species, belonging to 17 genera, of scale insects have been recorded in Turkmenistan from 20 species of gramineous plants, family Poaceae (---Gramineae). Eighteen of these species were also recorded in other regions of Central Asia, whereas seven species are known only from Turkmenistan.

The recorded scale insects belong to six families, namely, Pseudococcidae, Eriococcidae, Coccidae, Diaspididae, Margarodidae and Aclerdidae. The majority of species, 15 in number, belong to the mealybug family (Pseudococcidae). The most frequently infested host plants are Phragmites australis, Erianthus purpurascens, Cynodon, Festuca, Agropyron, Stipa and Sorghum.

Thirty-nine species of parasitic Hymenoptera, family Encyrtidae, were reared from 14 species of the above mentioned scale insects, mainly from mealybugs. Complexes of parasitoids are very common in Eriopeltisfestucae (Fortscolombe) (Coccidae), on Agrothrigia androssovii; Adelosoma phragmitidis Borchsenius and Trionymus copiosus Borchsenius (Pseudococcidae) on Ph. australis; Nipponaclerda turanica (Archangelskaya) (Aclerdidae) on Ph. australis. The encyrtids which parasitize Pseudocoocidae and Aclerdidae on Erianthus purpurascens and on Ph. australis are the most specific. (L)

252 Meetings

Model for the Prediction of Egg-Laying and Egg-Hatching in Spring Populations of the Olive Scale, Parlatoria oleae (Colv~e) (Diaspididae)

Nili Pinhassi, 1 David Nestel 2 and David Rosen 1 1Dept. of Entomology, The Hebrew University of Jerusalem, Faculty of

Agriculture, Rehovot 76100; and adept, of Entomology, ARO, The Volcani Center, Bet Dagan 50250, Israel

The timing, and association with temperature, of the phenological events (egg-laying and egg- hatching) of the spring generation of the olive scale Parlatoria oleae (Colv~e) (Coccoidea: Diaspididae) have been studied for 3 years in field populations of the scale in northern Israel. The results, which have been gathered at different elevations in apple orchards (replicates), show that there is a correlation between the accumulation of degree-days and the onset of insect phenological events. We are also studying the relationship between the phenology of olive scale populations and the phenology of the apple tree, with the aim of using the phenological events of the tree as a biofix. The data are being analyzed with linear models, and we expect to create a predictive model to be included in an IPM scheme to control this pest in Israel's deciduous orchards. (L)

The Economic Importance of Citrus Scale Insects in Israel (1984.1994) ~

Ben-Ami Peleg I and Itzhaq Bar-Zakay 2 ~The Israel Cohen Institute for Biological Control, Citrus Marketing

Board of Israel, Bet Dagan 50250; and 2Extension Service, Ministry of Agriculture, Tel Aviv 61700, Israel

During the last decade, significant changes have occurred in the economic importance of scale insect pests on citrus in Israel. The California red scale (CRS), AonidieUa aurantii Maskell (Diaspididae) was until the mid-1980s a destructive pest due to a remarkable build-up of resistance to organophosphorous (OP) scalicides and disrupted biological balance. Since the mid-1980s the pest has been under satisfactory control due to the use of the IGR Tiger (pyriproxyfen), and improved biological balance. The Florida wax scale, Ceroplastesfloridensis Comstock (Coccidae), is occasionally a significant pest, causing considerable damage. Improved biological balance helps to maintain the pest below economic importance. However, under certain climatic conditions, pest outbreak has occurred and required chemical control. The pest developed resistance to carbamates (carbaryl, earbosulfan) which had been effective in controlling the scale until the mid-1980s. Using OP scalicides resulted in infestation by an A. aurantii population. IGRs, mainly pyriproxyfen, provided satisfactory control of the pest. The citrus mealybug, Planococcus citri (Risso) (Pseudococcidae), is an important citrus pest in certain regions of Israel. In recent years we have observed a decrease in susceptibility of the mealybug to scalicides, causing a reduction of the efficacy of chemical control. Efforts have been made to enhance biological control of the pest. The cottony-cushion scale, lcerya purchasi (Maskell) (Margarodidae), was a serious pest in the northern part of the country. As a result of improved biological balance due to the use of selective chemicals, as well as the introduction of the parasitoid Cryptochaetum iceryae Williston (Cryptochaetidae), the scale is now considered a minor pest. (L)



Release and Recovery of Pesticide-Resistant Aphytis Strains in Israeli Citrus Orchards

Abraham Havron, 1 David Rosen 1 and Amos Rubin 2 IThe Hebrew University of Jerusalem, Faculty of Agriculture,

Rehovot, 76100; and 2Biological Control Laboratory & Consulting Service, 14 Rahavat Ilan, Givat Shmue151905, Israel

Aphytis lingnane~& Compete (Hymenoptera: Aphelinidae), an effective natural enemy of the California red scale (CRS), Aonidiella aurantii (Maskell) (Diaspididae), established in Israel, was selected for resistance to azinphos-methyl. A field population from a heavily sprayed citron orchard had shown ca tenfold resistance to azinphos-methyl relative to a susceptible laboratory strain. Upon selection by both the mass and male selection procedures, this resistance was further increased eighffold. This strain was released in the coastal plain of Israel against CRS, and in the Philippines against CRS and Unaspis citri (Comstock) in citrus orchards.

Recovery samples from Israeli release sites were propagated, tested for azinphos-methyl resistance, and compared with pre-release populations from the same locations. Mean LC5o values of post-release tests were higher than comparable pre-release tests, but the differences were not significant. Several seasons of commercial pesticide application may be required for appraisal of the released strain's competitive advantage.

Aphytis melinus DeBach, another effective natural enemy of the CRS introduced and established in Israel, has recently been reported only from the eastern Jezreel Valley, and was not recovered in our pre-release surveys. This species was selected for resistance to carbaryl in California. The resistant strain was imported, propagated and released on citrus in three different climatic regions of Israel, and has been recovered from all of them. In the hot, dry region of En Gedi, it oumumbered all other CRS parasitoids. (L)

Scale Insects on Citrus in Centra l Tamaul ipas , Mexico

Juan Fidencio Luna-Salas and M.E. Martinez-Shio Facultad de Agronomia, Universidad Autdnoma de Tamaulipas, C.U.

'Adolfo Lopez Mateos', Cd. Victoria, Tamaulipas 87149, Mexico

Citrus is an important crop in Central Tamaulipas, Mexico, with an area of 35,000 ha, mainly Valencia oranges. Armored scale insects, Diaspididae, are significant pests of the crop in this State. In order to improve their control, a survey of these pests was initiated.

Seven orchards of Valencia oranges, with trees of different age (5-35 years), were taken at random. Samples of branches, leaves and fruits were taken from the inner and outer parts of the foliage, and from low, medium and high levels of the trees.

The California red scale, Aonidiella aurantii (Maskell), was the most common species, infesting leaves, branches and fruits. It was present on all parts of the trees but the largest population was recorded on the lower external part of the foliage.

The glover scale, Lepidosaphes gloverii (Packard), was the second most common species. It was present only on branches and leaves of the lower inner part of the foliage. Both the California red scale and the glover scale were more abundant on the west side of the trees.

Other scale insects were recorded, although in low numbers: the cottony cushion scale, Icerya purchasi (Maskell); the Florida red scale, Chrysomphalus aonidum (L.); and the Mediterranean black scale, Saissetia oleae (Olivier). (L)

254 Meetings

The C i t ru s Snow Scale, Unaspis citri (Comstock) (Diasp id idae) , in T a m a u l i p a s , Mexico

Enrique Ruiz-Cancino and J.M. Coronado-Blanco Facultad de Agronomia, Universidad Autdnoma de Tamaulipas, C.U. 'Adolfo

Lopez Mateos', Cd. Victoria, Tamaulipas 87149, Mexico

Tamaulipas is a major citrus-producing State in Mexico, with 35,000 ha of citrus cultivars, mainly Valencia oranges. Unaspis citri (Comstock) has been recorded in central Tamaulipas since 1977 on lemons in the city of Llera. Severe infestations of the citrus snow scale causse defoliation of shoots and branches, cortex hardening, and grooves in the cortex; tree vigor deteriorates, fruit production is reduced and the tree may die. The pest spreads very slowly and at present it is found only at Llera and G6mez Fari~is, mainly on Valencia oranges.

This research is part of a major project on citrus pests and their natural enemies in Tamaulipas which was started in 1990. The study reported here was begun in May 1992, aimed at detecting the distribution of U. citri in the State, and studying its infestation levels and the identity of parasitoids present in a citrus grove at Llera.

Three hundred and nine trees were surveyed in order to determine the infestation rates. The samples were taken at three levels of the tree: low - from the base to lm above the trunk; to the division of branches; and high - over the branches and upper stratum. The results show that 206 tr_ees had a low level of infestation (0--9 scales__per 10 cortex samples of 0.5 cm 2, at random X = 3.5); 87 had a medium level (10--30 scales, X = 16.3); and 16 had a high level of infestation (30-60 scales, X = 52.1) and grooves in the cortex of the trunk and branches.

The parasitoids were sampled on ten trees of each infestation rate. Three traps per tree were attached to the trunk and/or branches. Three species of the Aphelinidae were recorded and are under study by specialists in the USA. The rate of parasitization was low, being at most 9.7% in the high rate of infestation. Pesticides applied against the Mexican fruit fly very likely have an adverse effect on the parasitoids of the citrus snow scale. (L)

Population Dynamics ofAonidieUa aurantii (Maskell) (Diaspididae) and Its Natural Enemies on Citrus

from 1976 to 1993 in the Mediterranean Region of Turkey

Nedim Uygun, Ismail Karaca and E. $ekero~lu Dept. of Plant Protection, Faculty of Agriculture,

University of Cukurova, 01330 Adana, Turkey

Studies of integrated pest management (IPM) in citrus orchards in Turkey have been carried out generally in old plantations. However, it was difficult to judge the success of IPM because of the difficulty in estimating the densities of the pest and beneficial insect populations in the orchard prior to initiation of the IPM programs. Therefore this project was carried out to determine how to implement an IPM program in a newly planted citrus orchard. This study was initiated in 1977 end is still being continued in lemon (18 ha), orange (12 ha), grapefruit (20 ha) and mandarin (20 ha) orchards, viz., a total of 70 ha citrus plantation area which was planted in 1976 in Adana.

During the first year the only pest was Aonidiella aurantii, which was introduced into the orchards on infested seedlings during orchard establishment. Later A. aurantii became a main pest. The pests Aphis citricola v.d. Goot, lcerya purchasi Maskell, Ceratitis capitata Wiedemann, Phyllocoptruta oleivora (Ashmead), Ceroplastes floridensis Comstock, Coccus


pseudomagnoliarum (Kuwana), Planococcus citri (Risso), Aceria sheldoni Ewing, Chrysomphalus dictyospermi Morgan, Parabemisia myricae (Kuwana), Dialeurodes citri (Ashmead), Asymmetrasca decedens (Paoli), Empoasca decipiens Paoli, and Cryptoblabes gnidiella Mill. were observed sporadically. Only P. oleivora and C. capitata increased to a population level which required control measures.

In this study, population dynamics and natural enemies of the key pest, A. aurantii, and some control practices for minor pests, P. oleivora and C. capitata, were recorded and described. (L)

The Oriental Scale, Aonidiella orientalis (Newstead) (Diaspididae): Biology, Phenology, Geographic Distribution and Natural Enemies in Israel

Manes Wysoki, 1 Yossi Israeli 1'2 and David Rosen 2 1Dept. of Entomology, ARO, The Volcani Center, Bet Dagan 50250;

and 2Dept. of Entomology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot 76100, Israel

The biology, phenology, geographic distribution and natural enemies of the Oriental scale, Aonidiella orientalis (Newstead) (Homoptera: Diaspididae), were investigated, A relatively new pest in Israel, it was first recorded on mango in 1980 in the Arava Valley, to which it had probably spread from neighboring countries. It has since dispersed to the north, and has become established in almost all mango-growing regions of Israel, especially around Lake Kinneret (Sea of Galilee).

The level of infestation is low in March and June, increases in July-August and peaks in October-December.

The pest causes damage to leaves, twigs and fruit. It has been found in Israel on ten plant hosts, including olive, guava, feijoa and acacia. Several natural enemies were found attacking it, among them the parasitoids Comperiella bifasciata Howard, Habrolepis aspidioti Compere and Annecke (Hymenoptera: Encyrtidae); Aphytis melinus DeBach, Aphytis lingnanensis Compere, and Encarsia sp. (Hymenoptera: Aphelinidae); the hyperparasitoids Marietta javensis Howard, Ablerus guadrff (Agarwal) (Hymenoptera: Aphelinidae) and Zaomma n.sp. near carinae Prinsloo (Hymenoptera: Encyrtidae); the predators Stethorus gilvifrons Mulsant, Chilocorus bipustulatus L. (Coleoptera: Coccinellidae), Chrysoperla carnea Stephens (Neuroptera: Chrysopidae); and the parasitic mite Hemisarcoptes coccophagus Meyer (Acarina: Hemisarcoptidae). (P)

Phenology ofKuwania rubra Goux (Margarodidae) and Its Parasitoid Mayrencyrtus merceti Hoffer (Hymenoptera: Encyrtidae) in Southern Italy ~

Gennaro Viggiani and M. Loia Dept. of Agricultural Entomology and Zoology, University of

Naples 'Federico II', 80055 Portici (NA), Italy

The phenology of Kuwania rubra Goux and its parasitoid Mayrencyrtus merceti Hoffer was studied in Campania (southern Italy) during the years 1991-1993.

The scale insect overwinters as a second or cyst stage in the crevices of the trunk and in the bark of branches. The last molt to adult female occurs from March-April to July-August. No males


256 Meetings

were observed. Oviposition takes place from April to August, but with a peak in May-June. Each female oviposits 20-60 eggs in a scant, waxy egg-sac. The mobile first larvae search for the crevices of the bark where they settle and reach the replete phase. Gradually the first larvae molt into a second or cyst stage, in which they overwinter. The development of this stage is very slow; it takes about a year and there is a relevant increase in size.

The endoparasitoid M. merceti develops only in the second or cyst stage of the host, which is available all year around. This species overwinters as young larvae, which reach the full stage in the spring. Adult emergence starts in late April and reaches a peak in June. The early females can oviposit in the late cyst phase and start a new generation ending in June-July. The other females, ovipositing later, will produce adult progeny in the subsequent, late spring. Only a few adults of the parasitoid emerge during autumn of the same year. (L)

Coccoids of Economic Importance and Their Control in the Republic of Georgia

Valentina A. Yasnosh Dept. of Biological Control, Plant Protection

Research Institute, 380062 Tbilisi, Republic of Georgia

In the Republic of Georgia, the Caucasus mountains divide the country into subtropical and drier regions.

In citrus groves, where 18 species of coccoids were recorded, the most harmful ones are Lopholeucaspis japonica (Cockerell), Chrysomphalus dictyospermi (Morgan), Ceroplastes japonicus Green and Ce. sinensis Del Guercio, whereas locally heavy infestations are caused by Aonidiella citrina (Coquillett), Chloropulvinaria aurantii (Cockerell) and Ch. floccifera (Westwood). Most of the other coccids are under good natural control. Sixteen species of entomophagous insects were introduced to improve biological control and several of them have become established, with good results. At present, a new program of integrated citrus pest control is being implemented.

In tea plantations, Ch. floccifera is the most common pest, followed by L. japonica, but infestations of the latter have decreased recently.

The most harmful species on grapevine are Planococcus ftcus (Signoret) and Neopulvinaria innumerabilis (Rathvon), whereas others (about ten) are not of economic importance. Harmful coccids on grape, as well as on tea, are controlled only by the coccinellid Cryptolaemus montrouzieri Mulsant. About 30 species infest fruit trees, but the most noxious is Quadraspidiotus perniciosus (Comstock), particularly in the eastern (dry) part of the country. Parlatoria oleae (Colv6e) and Epidiaspis leperii (Signoret) are harmful too. In coastal regions, damages are caused by L. japonica, Pseudococcus affinis (Maskell), Ceroplastes spp. and others.

On mulberry, about ten species are recorded but they are not of economic significance. Recently, an infestation by Pseudaulacaspis pentagona (Targioni-Tozzetti) was recorded near Batumi.

The largest numbers of coccid species occur on ornamental and urban plants. Control measures against these pests are discussed. The complexes of natural enemies

attacking coccoids have been studied, in order to provide rational control measures. (L)


Armoured Scale Insect (Diaspididae) Pests of Fruit Orchards and Their Control in the Republic of Georgia ~

Guram Aleksidze Plant Protection Research Institute, 380062 Tbilisi, Republic of Georgia

Several species of armoured scale insects (Coccoidea: Diaspididae) are important pests of fruit trees in the Republic of Georgia, namely, Quadraspidiotus perniciosus (Comstock), Parlatoria oleae (Colv~e), Lepidosaphes ulmi (L.), Epidiaspis leperii (Signoret) and Quadraspidiotus ostreaeformis (Curtis). In Georgia the first species develops two annual generations, the second two to three, whereas the rest are univoltine.

Populations of these pests are regulated to a considerable extent by the predators Chilocorus bipustulatus (L.) and C. renipustulatus (Scriba), and by the parasitoids Encarsia perniciosi (Tower), Aphytis proclia (Walker), A. maculicornis (Masi) and A. mytilaspidis (Le Baron).

Chemical control of the pests is carried out by application of mineral oils, which are effective against the overwintering stages, and by organophosphorus or pyrethroid products against the hatching crawlers. (L)

Distribution, Population Fluctuations and Natural Enemies of the White Peach Scale, Pseudaulacaspis pentagona (Targioni-Tozzetti)

(Diaspididae), in the East Mediterranean Region of Turkey

Lerzan Erkilir 1 and Nedim Uygun 2 I Plant Protection Research Institute, Ministry of Agriculture

and Rural Affairs, 01321 Adana; and 2Dept. of Plant Protection, Faculty of Agriculture, University of Cukurova, 01330 Adana, Turkey

Peach is grown in the mountainous area of the East Mediterranean Region of Turkey, but during the last decade it has also been cultivated in the Cukurova plain of the region. The white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti), is one of the main pests of peach trees, being found over almost all the peach-growing area in the region. However, there has been no study of the distribution, population fluctuations, host plants and natural enemies of the pest in the East Mediterranean Region of Turkey.

The aim of this project was to determine the distribution and population fluctuations in certain orchards, host plants, and of natural enemies of P. pentagona in the region. The results indicated that P. pentagona was common in all peach-growing localities, with very heavy infestations being observed in the Mersin and Silifke districts. P. pentagona overwintered as a gravid female both in the plain and in the mountainous area. The pest develops three to four generations per year in the Cukurova plain and only two generations in the mountainous area. In addition to on peach, the insect was also found on kiwi, mulberry, some other fruit trees, as well as on some weeds.

The predators Chilocorus bipustulatus (L.) and Cybocephalus fodori minor Endrody-Young, and the parasitoid Encarsia berlesei (Howard) and some other species, were determined as the natural enemies of the pest. (L)


258 Meetings

Interrelations of Quadraspidiotus zonatus (Frauenfeld) (Diaspididae) and Its Encyrtid Parasite of the Genus Metaphycus Mercet

Elzbieta Podsiadlo Dept. of Zoology, Agricultural University, 02766 Warsaw, Poland

Quadraspidiotus zonatus (Frauenfeld) is a common species in Poland. It lives on oaks and settles on the young trunks, branches and twigs. It is bisexual and univoltine under the climatic conditions of Poland; it overwinters as the fertilized female. Preliminary observations on the biology of Q. zonatus and its parasites were carried out in 1991.

The females of the scale begin to oviposit in the second half of June. The first-instar nymphs hatch after several days. The male crawlers move to leaves and settle on the underside, whereas the female crawlers remain on the bark. The second-instar nymphs appear in the middle of July. Prepupal and pupal stages occur predominantly in August. Adults appear in the second half of August and the first half of September.

Hitherto~ only aphelinid parasitoids were recorded from Q. zonatus, but during these studies a species of Metaphycus (Encyrtidae) also was found parasitizing Q. zonatus. The Metaphycus sp. has two generations per year: the overwintering one and the summer one. It overwinters as a larva within the host's adult females. Adult parasitoids emerge in July. The summer generation of the parasite develops in the second-instar nymphs of the host. The adults emerge at the end of August and in September. (L)

Phenology, Embryonic Diapause and Importance of Natural Enemies ofLepidosaphes ulmi (L.) (Diaspididae) on Olive Trees in Greece

Panayotis Katsoyannos 1 and G.J. Stathas 2 1Benaki Phytopathological Institute, GR 145 61 Kiphissia, Athens; and 2National Agricultural Research Foundation, Plant Protection

Institute of Thessaloniki, 57001 Thermi-Thessaloniki, Greece

Lepidosaphes ulmi (L.) (Diaspididae) develops one annual generation on olive trees in Attica, Central Greece. Observations on the phenology of this species were carried out in two localities in Greece, namely, Nea Makri (during 1989-1990) and Lavrion (during 1990-1991 and 1991-1992). Eggs began hatching in mid-April, after a diapause of more than 8 months. The first males appeared in late May in 1990, and in early June in 1991. Immature females were observed in early June (1990) and late June (1991), while ovipositing females were present in late June (1990) and mid-July (1991). The fecundity was 65 + 16 eggs per female.

The eggs laid by these females in the field entered diapause and hatched, after overwintering, the following April. Eggs collected from Lavrion on July 15, 1991, and transferred to the laboratory (25 + I~ L:D, 16:8 photophase and 65 +5% r.h.) started hatching 256 days later; however, of the 465 eggs collected, only 2.6% were viable. For 333 eggs collected from the same locality and transferred on Jan. 9, 1992, to the above laboratory regime, the incubation period was 29 days and 66.4% were viable. Eggs collected and transferred to the laboratory on Feb. 26, 1992, hatched within 13 days (99.6% viable), and those collected on March 28, 1992, hatched after 11 days (100% viable).

Two predators were preying on this diaspidid: Hemisarcoptes malus (Shimer) (Acarina: Hemisarcoptidae) being of major importance, and Cybocephalus fodori Endrody-Younga (Coleoptera: Nitidulidae) of minor importance. At Lavrion (1991), H. ma/us was preying on live or


partly destroyed L. ulmi at the following rates: 12.7% of second-instar females, 16.5% of male pupae, 41.4% of young females and 48.6% of ovipositing females. At Lavrion, the population of L. ulmi decreased by 95 times in one year, from 1.9 adults/cm 2 on April 4, 1991, to 0.02 adults/cm 2 on April 27, 1992. This reduction is attributed mainly to predation by H. malus. Adults and larvae of C.fodori were found in Lavrion in small numbers between May and July. (L)

Natural Enemies and Other Arthropods Associated with Matsucoccusjosephi (Margarodidae) in Cyprus:

An Ecological Perspective

Miri Halevy, 1 Zvi Mendel, 2 Fabienne Assael 2 and David Rosen 1 1Dept. of Entomology, The Hebrew University of Jerusalem,

Faculty of Agriculture, Rehovot 76100; and 2Dept. of Entomology, ARO, The Volcani Center, Bet Dagan 50250, Israel

The Israeli pine bast scale, Matsucoccus josephi Bodenheimer & Harpaz, occurs at low

densities on Pinus brutia ssp. brutia in the Eastern Mediterranean. It causes almost no damage to brutia pine, as opposed to the severe decline and mortality it causes to Aleppo pine in Israel. A survey of natural enemies and other axthropods associated with the scale was conducted in natural stands of P. brutia at three sites in Cyprus (Kapoura, Paphos Forest and College Fores0. The species recorded belong to the following orders and families: Coleoptera (numerous families), Hemiptera (Anthocoridae), Hymenoptera (Formicidae), Raphidioptera (Raphidiidae), Acari (Smarididae), Araneae (Philodromidae, Salticidae, Filistatidae, Clubionidae), and Pseudoscorpiones (Cheliferidae). Community structure was determined using indexes for species richness, heterogeneity and species equitability. Environmental factors governing species richness were identified. Patterns of species abundance were determined and interpreted according to statistically and biologically oriented models. (L)

E: BIOLOGICAL AND CHEMICAL CONTROL

Biological Control of Scale Insects in Interior Plantscapes ~

Mike Rose and Steve Stauffer Dept. of Entomology, Texas A&M University, College Station, TX 77843, USA

Homoptera are the major plant pests in interior plantscapes. Scale insects (Coccoidea) comprise more than half of the pest species encountered thus far in U.S. botanical gardens, commercial plantscapes, conservatories, zoological gardens and ecosystem representations. The integration of plants and animals in these systems, along with safety issues, requires improved pest control practices. Biological control by natural enemies is an environmentally optimal, long-term, and historically sound method of scale insect population regulation. The development of biological control programs for key pest species will be discussed from the aspects of systematics, natural enemies, efficacy evaluations, methodologies, and interaction among horticulturists, insectaries and researchers. (L)


260 Meetings

Biological Control of Citrus Snow Scale, Unaspis citri (Comstock) (Diaspididae), in South East Queensland

Daniel Smith I and Daniel Papacek 2 I Maroochy tlorticultural Research Station, Department of Primary

Industries, Nambour 4560, Queensland; and 2Integrated Pest Management Pry Ltd., Mundubbera 4626, Queensland, Australia

Citrus snow scale, Unaspis cirri (Comstock) (Coccoidea: Diaspididae), has been a major pest of citrus in eastern Australia, only partially under biological control and difficult to control with pesticides.

In 1977 and 1981 two parasitoids, namely, Aphytis lingnanensis Compere HK1 and HKJ, were introduced from Florida and Japan but did not improve control. During the 1980s an intensive search was conducted for promising parasitoids in southern China and two further parasitoids (Aphytis gordoni DeBach & Rosen and Encarsia inquirenda (Silvestri) were introduced, again without success. In 1988 a fifth parasitoid (Aphytis sp.) was introduced from Thailand, and over the next 4 years about two million wasps were reared and released. In 1990, the Oriental ladybird, Chilocorus circumdatus Gyllenhal, was first observed in Queensland feeding on U. citri. During 1990-91 it was field collected and laboratory reared, released and established in citrus areas throughout Queensland.

Citrus snow scale and its natural enemies were studied during 1989-1993 on six citrus blocks in Queensland, Australia. The Thai Aphytis showed initial promise but exercised little control of scales infesting the trunk and main limbs. Good control was achieved in all blocks by C. circumdatus and severe infestations were rendered subeconomic within two seasons. Ladybird numbers averaged about 20 per tree in the subcoastal blocks and about 5 per tree in the coastal blocks (with lower scale infestations). Populations in some heavily infested orchards were estimated at up to 1000 ladybirds per tree. The ladybirds were persistent and a few usually remained per tree even when the scale was reduced to a low level.

The ladybird did not eradicate the scale and when it was affected by pesticides (either directly sprayed or by drift), there was a resurgence of U. citri. However, C. circumdatus has alleviated a major threat posed by U. citri, and orchards of trees once white due to dense scale infestations, are now under satisfactory control of the pest. (L)

Release of Chilocorus kuwanae Silvestri (Coleoptera: Coccineilidae), with Notes on Its Development in Tennessee

P. Lambdin Dept. of Entomology & Plant Pathology,

University of Tennessee, Knoxville, TN 37901, USA

Species of Euonymus are among the most preferred omamental plants sold in Tennessee. Unfortunately, Unaspis euonymi (Comstock) is a serious pest of this species, with heavy infestations causing discoloration, die-back, and eventual death of the plant. As such, species of Euonyrnus have often been replaced with other ornamental plantings, and some nurseries have reduced or eliminated production of Euonymus. Because releases of Chilocorus kuwanae have successfully controlled infestations of U. euonymi in several parts of the LISA, the objectives of this work were to establish this predator throughout the state and evaluate its development and behavior.


Field Releases: Lady beetles were released at four to six sites (25 adults/site) onto infested plants in middle and east Tennessee annually from 1990o1993. Fewer than 500 live adult scale insects were observed at two release sites by September 1990. In 1991-92, lady beetles were recovered at one site in Knox County.

Prey Selectlon and Development: In laboratory tests, a random searching pattern for prey was observed in all developmental "stages. The predator was evaluated against Quadraspidiotus perniciosus, Chionaspis pinifoliae, Quadraspidiotus salicisnigrae and U. euonymi. No differences in the length of time required to find the food sources were observed. However, once prey was discovered, all stages fed longer on eggs of the euonymus scale than of the other scales. Specimens were unable to develop to adulthood on either pine needle scale or willow scale eggs. A constant increase in the number of eggs consumed was recorded for the various stages of the predator. In observations on 25 first instars, an increase in weight gain was recorded from 0.9 (0.1-5) mg for first instars to 7.8 (5-15) mg for adults.

Ovipositlonal Behavior: Fecundity of the lady beetle increased with increase of prey consumption. The preferred ovipositional site for C. kuwanae eggs (0-6/site) was under female scales (69%). The survival rate of eggs deposited under the scale's test was higher than that recorded for other ovipositional sites. Other sites included advantageous roots (10%), cut ends of branches (16%), and the undersides of leaves (5%). Two mated females produced 45 and 65 eggs, respectively, over a 25-day period under laboratory conditions. Egg eclosion occurred 4-6 days after oviposition. Field and laboratory evaluations have demonstrated the effectiveness of the predator against the euonymus scale. Such biological control agents offer a sustainable, alternative means of area-wide, long-term pest suppression that is environmentally safe, economical, and compatible with other control tactics. (P)

Thinning the Population of the Florida Wax Scale, Ceroplastesfloridensis Comstock (Coccidae), as an Optional IPM Procedure in Citrus Groves in Israel

Aharon Yardeni 1 and Elyakim Shapira 2 1Extension Service, Ministry of Agriculture, Rehovot 76262; and

2 Moshav Yesodot 76810, Israel

The Florida wax scale, Ceroplastes floridensis Comstock (Coccoidea: Coccidae), is a major pest of citrus groves in Israel and is usually controlled by non-selective insecticides. The pest has an advantage over its natural enemies in the build-up of its population in a 'clean' grove, following pesticidal control, due to the ability of its wind-dispersed crawler to invade the grove, and the tremendous rate of increase of its populations. Thinning the invading generation of the Florida wax scale larvae to low population densities by a nutritional spray of 4% potassium nitrate with 2% spray oil, once a year, obviated the need to control the pest by any other means during 7 years, in a general IPM procedure at the Yesodot citrus grove (southern coastal plain, Israel). Thinning the population of a pest might be an additional option in IPM. (L)

262 Meetings

Effectiveness of a New Insecticide for Control of the San Jose Scale, Quadraspidiotus perniciosus (Comstock) (Diaspididae),~

on Peach Trees in Northern Greece

Stergios S. Paloukis and Emmanuel I. Navrozidis National Agricultural Research Foundation, Plant Protection Institute

of Thessaloniki, 57001 Thermi-Thessaloniki, Greece

The effectiveness of the new IGR insecticide Aware (CGA 59205) was evaluated for control of the San Jose scale, Quadraspidiotus perniciosus (Comstock) (Diaspididae), on peach trees. The experiments were carried out in northern Greece (Macedonia), where this diaspidid is a most injurious pest of peach trees. The insecticide was applied in two treatments, spring and summer, at the rate of 10 and 15 g a.i./ha, respectively. The control treatment consisted of methidathion at the rate of 55 g a.i./ha.

The rate of mortality of the scale as a result of application of the new product was higher than 95%. Applications at the above rates reduced parasitization by the endoparasite Encarsia perniciosi flower) (Aphelinidae) only slightly, whereas methidathion reduced the parasitization by more than 95%, 20 days after application. (L)

A Decade of Integrated Control of Persimmon Pests in Israel

Amos Rubin Biological Control Laboratory & Consulting Service,

14 Rahavat llan, Givat Shmue151905, Israel

The major pests of persimmon, Diospyros kaki (Ebenaceae), in Israel are the citrus mealybug, Planococcus citri (Risso), and the Mediterranean fruitfly, Ceratitis capitata Wied. Persimmon is also infested by some minor pests, namely, Cryptoblabes gnidiella, Retithrips syriacus and the Florida wax scale, Ceroplastesfloridensis.

Prior to 1984, growers used to control the citrus mealybug with three prophylactic sprays of synthetic insecticides, applied in July, August and September. Since 1984 the mealybug populations have been monitored in several orchards by fortnightly searches (from June to October) for larvae and females, on 100 fruits per hectare, supplemented by the number of males caught in pheromone traps. Sprays, if necessary, were applied, according to the results of the monitoring. Consequently, only one spray per season was applied between 1984 and 1993. Augmentative release (from June) of the encyrtids Leptomastidea abnormis, Anagyrus pseudococci and Leptomastix dactylopii, and of the predators Cryptolaemus montrouzieri, Nephus reunioni (Coccinellidae) and Symphaerobius sanctus (Symphaerobiidae), improved the natural control of the mealybug.

The medfly is controlled in the persimmon orchards (a total of about 1000 ha), by protein- hydrolysate-baited malathion by aerial sprays. Counts of approximately 100,000 persimmon fruits during 1984-1993 indicate that the natural population of spiders constitutes an important biocontrol factor of the citrus mealybug. (L)


Integrated Contro l Methods of the Citrus Mealybug, Planococcus citri (Risso), in Crete, Greece

Stelios Michelakis I and H.A. Hamid 2 1Agricultural Research Centre of Crete, Chania-Crete,

Agrokipio 73100; and 2Mediterranean Agronomic Institute of Chania, Alsyllion Agrokipio 73100, Greece

The citrus mealybug, Planococcus citri (Risso) (Coccoidea: Pseudococcidae), is a major pest of citrus orchards in Crete. In order to reduce the use of chemical insecticides, experiments were carried out to introduce integrated control methods for the pest.

The predator Cryptolaemus montrouzieri Mulsant was released at three predator/prey ratios (1:10, 1:15, 1:30), on potted orange trees which were raised in a greenhouse. The releases at 1:15 significantly reduced the population of the mealybug.

The controlling effect of C. montrouzieri was compared with that of the predator Nephus reunioni, in a ratio of 1:15, and with the insecticide methidathion (at a concentration of 0.1%), under controlled conditions of 25-30~ and 55-70% r.h. The mealybug was maintained on pumpkin squash, Cucurbita moschata Duch. C. montrouzieri caused a significant reduction in mealybug population when compared with N. reunioni, but a greater reduction was obtained by methidathion.

We evaluated the possibility of hindering grapefruit infestation by hindering the migration of the mealybug from the roots to the upper parts of trees. Smearing an adhesive material around the trunks significantly reduced the mealybug population on fruits. This physical control method can be combined with other methods in the integrated control of the citrus mealybug.

The insecticidal effect of petroleum oil (at concentrations of 1.5% and 2%) was compared with methidathion (0.15%), in a mandarin orchard. Oil application in August was not effective in reducing the population, but the 2% spray was more effective than the 1.5%. (L)

F: NATURAL ENEMIES: BIOLOGY AND HOST INTERACTION

Some Peculiarities of Host Specificity of Coccid-Inhabiting Chalcidoid Parasitoids (Hymenoptera) ~

Eugeny S. Sugonyaev Zoological Institute, Russian Academy of Sciences,

199034 SLPetersburg, Russia

Preference of certain host taxa is typical for parasitoid species of most genera of the families Encyrtidae and Aphelinidae. For example, in the genera Anicetus, Blastothrix, Bothriophryne, Diversinervus, Encyrtus, Metaphycus, Microterys, Trichomasthus, Aneristus and Coccophagus, more than 80% of the species are parasites of coccid scales (farn. Coccidae), whereas the remaining few attack hosts from one to seven other families of Coccoidea. These data indicate a rather high level of generic specificity of parasitism attained in the Chalcidoidea, and at the same time reveal a small part of species with trophic relations (TR) deviating from the general trend, and referred to as 'aberrant'. The obvious minority status of aberrant species and the variety of taxonomic

~ not presentedat the Symposium.

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composition of their hosts probably indicate the secondary character of their TR. Moreover, the secondary nature of adaption to new host taxa in the genus Metaphycus is corroborated by morphological characters, i.e., a general diminution of body size, and a parallel reduction of joint number in both maxillary and labial palps, that are common to the groups of species specializing in asterolecaniid and diaspidid scale insect hosts.

Several characteristics play a preadaptive role and determine the background for formation of aberrant TR.

(i) Rate of speciation in a genus. In fact, the highest proportions of aberrant species are known in the largest genera, Metaphycus (211 species), Microterys (126) and Coccophagus (125), i.e., for genera with intensive speciation, that has probably created a basis for occupation of new adaptive zones.

(ii) Morphological structures of the abdomen, especially of the fernale ovipositor, permitting oviposition into potential hosts of a different habitus.

(iii) Dominance of potential hosts in given ecosystems, that guarantees the probability of contact and coevolution of a parasite with a new host.

(iv) Similarity of mode of life of the main and a potential host, especially in seasonal development and location.

(v) Morphological similarity of a potential and the main host.

Walking and Other Non-Reproductive Behavior in Two Species of Encarsia (Hymenoptera: Aphelinidae) Used in

Biological Control of the White Peach Scale (Diaspididae)

A. Panis, E. Oi and Ch. Pinet INRA Laboratoire de Biologie des Invertebrgs, 06560 Valbonne, France

The white poach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) (Diaspididae), occurs in all poach-growing areas of France and is generally controlled by natural enemies, among them Encarsia berlesei (Howard), which was established in 1919. Nevertheless, outbreaks of the pest occur frequently and are probably affected by climate. Attempts have been made for 3 years to introduce and establish the parasite Encarsia diaspidicola (Silvestri). Both Encarsia species are uniparental, endoparasitoids of the scale, and can be separated from each other, as dead specimens under high magnification. However, no morphological differences are available to distinguish between the species, as is required for our laboratory studies.

Non-reproductive behavior - particularly walking, hopping and posture when coming to rest - of these Encarsia species was observed in a small arena. Description and statistical analysis of the behavioral features show that these are very similar in both species. To the naked eye it appears that E. diaspMicola moves much faster than E. berlesei. When an insect exhibits doubtful behavioral features, identification is completed under a hand lens. The anterior wings are wider in E. berlesei than in E. diaspidicola, so that when folded above the abdomen they overlap more completely in the former, forming a continuous margin at the apex, which is expanded and wider than the abdomen. In E. diaspMicola, the margin of the folded wings forms a broken, apical outline and is shorter than the width of the abdomen. (L)


Biosystematic Studies in the Aphytis lingnanensis Complex

Yael Argov, 1 Einat Zchori-Fein 2 and David Rosen 2 tCitrus Marketing Board of Israel, The Israel Cohen Institute for

Biological Control, Bet Dagan 50250; and 2Dept. of Entomology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot 76100, Israel

Aphytis lingnanensis DeBach (Hymenoptera: Aphelinidae) is a minute parasitic wasp that, like all other members of its genus, develops exclusively as a primary ectoparasite of armored scale insects. This parasite is one of the most effective natural enemies of the California red scale, Aonidiella aurantii (Maskell), and has been successfully used in biological control of this important pest. In the systematic revision of Aphytis, Rosen and DeBach (1979) stated that the lingnanensis group may contain several undescribed species. The present study was carried out in order to establish the systematic relationships between morphologically identical biparental and uniparental 'strains' of A. lingnanensis from different geographical sources. Reciprocal crosses were performed between A. lingnanensis from California (the type population) and strains from South Africa, Israel, the Philippines (biparental and uniparental), and a mixture from Texas and Hong Kong. The South African strain was also crossed with the Texas-Hong Kong mixture. In order to establish the biosystematic status of the uniparental strain, males from California, South Africa, Israel, and the Philippines were mated with uniparental females, and the female spermathecae were dissected and examined for the presence of sperm. In addition, production of males was induced in the uniparental strain by antibiotic treatments, and reciprocal crosses were conducted between that strain and the Californian strain. The results showed that A. lingnanensis from California was compatible with all biparental strains but the South African one. It was also incompatible with the uniparental strain from the Philippines. We therefore conclude that these two strains are different from A. lingnanensis, and should be considered as distinct species. (L)

Parasitoid Encapsulation by Soft Scale Insects

Daniel Blumberg Dept. of Entomology, ARO, The Volcani Cemer, Bet Dagan 50250, Israel

Encapsulation is a common defense mechanism of a host insect in response to attack by an internal parasitoid. In the process of encapsulation, the host forms a capsule around the parasitoid egg or larva, which is usually comprised of host blood cells and the pigment melanin. The capsule may kill the parasitoid and thus prevent successful parasitism.

Encapsulation may adversely affect the degree of biological control effected by parasitoids as it may either prevent the establishment of exotic parasitoids in new regions or reduce parasitoid efficacy. Likewise, a high incidence of encapsulation may cause difficulties in mass rearing of parasitoids.

Among the important factors that may affect the frequency of parasitoid encapsulation in soft scale insects are (a) the host insect: its age, strain, physiological condition, and whether or not it is superparasitized; (b) the rearing temperature; and (c) the host plant, Intentional weakening of the host by exposure to extreme temperatures (e.g. 40~ prior to parasitism may bring about a considerable reduction in the incidence of encapsulation. This can be considered an important factor in improving the mass rearing of parasitoids. (P)

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Encapsulation of Eggs of the Encyrtid Parasitoid Metaphycus stanleyi Compere by the Pyriform Scale,

Protopulvinaria pyriformis Cockerell (Coccidae)

Daniel Blumberg Dept. of Entomology, ARO, The Volcani Center, Bet Dagan 50250, Israel

Since the early 1980s the pyriform scale, Protopulvinaria pyriformis Cockerell (Homoptera: Coccidae), has been an important pest of avocado in the coastal plain of Israel.

Encapsulation of eggs of the introduced parasitoid Metaphycus stanleyi Compere (Hymenoptera: Encyrtidae) by the scale, under both greenhouse and field conditions, occurred almost the year round. Encapsulation rates varied considerably during the year and were correlated with the ambient temperatures. The rates of efficient encapsulation (percentage scales wherein encapsulation completely prevented parasitoid development) in scales infesting Hedera helix and Scheffiera arboricola under greenhouse conditions, were lowest during December to May (6-17%) and highest during July to September (78-100%); in scales infesting avocado at Bet Dagan, rates were lowest during October to May (0-11%) and highest during June to August (54-75%). Under greenhouse conditions, encapsulation rates did not differ in scales grown on H. helix from those grown on S. arboricola, but were significantly lower in scales grown on avocado. (P)

Par thenogenesis Induced by Microorganisms in Aphytis

Einat Zchori-Fein and David Rosen Dept. of Entomology, The Hebrew University of Jerusalem,

Faculty of Agriculture, Rehovot 76100, Israel

Virtually all Homoptera have at least one type of symbionts that are confined to mycetocytes or mycetomes and are invariably transmitted transovarially. In the Coccoidea, no data are available about the role played by such symbionts in the physiology of their hosts, although there is indirect evidence of their involvement in nitrogen, carbohydrate or steroid metabolism.

Parasitic wasps of the genus Aphytis (Hymenoptera: Aphelinidae) are ectoparasites of Diaspididae, and are by far the most effective natural enemies of these important pests of crops and ornamentals. Most of the species in this genus exhibit the normal arrhenotokous reproduction of Hymenoptera (unfertilized eggs developing into males and fertilized eggs into females), but some reproduce by thelytoky (females producing female offspring without fertilization by males). Antibiotic treatments can induce the production of males in some of the thelytokous species. In such species, intercellular rickettsia-like microorganisms were found in the ovaries and eggs of untreated females but could not be found in antibiotic-treated females, nor in closely related arrhenotokous strains. The occurrence of revertible thelytoky in Aphytis, combined with the presence of microorganisms in untreated uniparental but not in antibiotic-treated biparental females, suggest that these symbionts somehow induce parthenogenesis. The possible influence these microorganisms may have on the fitness of their hosts was discussed. (L)


Host-Parasitoid Relations in Aphytis lingnanensis Compere

Shai Ben-Shalom, 1 Yoram R/Jssler 2 and David Rosen 1 1Dept. of Entomology, The Hebrew University of Jerusalem, Faculty

of Agriculture, Rehovot 76100; and 2Citrus Marketing Board of Israel, The Israel Cohen Institute for Biological Control, Bet Dagan 50250, Israel

Parasitic wasps of the genus Aphytis (Hymenoptera: Aphelinidae) develop as primary ectoparasitoids on armored scale insects (Homoptera: Diaspididae). We examined the development of A. lingnanensis on third-instar females of the oleander scale, Aspidiotus nerii (Bouch~). The Aphytis female normally paralyzes the host during oviposition. A technique of transferring neonate larvae was utilized to vary parasitoid population densities upon individual scale insect hosts. This technique makes it possible to separate the role of the adult Aphytis female in the host selection process ('host acceptance') from that of the larvae ('host suitability'). Parasitoid development upon hosts that had not been previously paralyzed by an adult wasp resulted in a high mortality rate at low larval density ('Allee effect'), indicating the potential ability of the scale insect to overcome partially the larval stages of its ectoparasitoids. This phenomenon is prevented during normal oviposition, when the host is paralyzed. In addition, we found that the parasitoid population can maintain itself even at extremely high densities, due to effective intraspecific predation among the young larval stages. This density-dependent mortality factor prevents eradication of the entire parasitoid population as a result of starvation. (L)

Effect of Several Species of Armored Scale Insects on the Parasitic Mite Hemisarcoptes coccophagus Meyer

Sergey Izraylevich and Uri Gerson Dept. of Entomology, The ltebrew University of Jerusalem,

Faculty of Agriculture, Rehovot 76100, Israel

Hemisarcoptes coccophagus Meyer (Astigmata: Hemisarcoptidae) is a parasitic mite attacking armored scale insects (Homoptera: Diaspididae); it has been used in Africa and New Zealand to control diaspidid pests. The mite is usually regarded as a generalist natural enemy. Herein we show that the host scales have a pronounced effect on its parasitization patterns. When latania scale, Hemiberlesia lataniae (Signoret), and oleander scale, Aspidiotus nerii Bouch~, concurrently infested acacia a'ees, mite prevalence and mean intensity per parasitized scale were much higher on the former than on the latter. Mite sex ratios were male-biased, moderately on latania scale and strongly on oleander scale. Mite fecundity was high on latania scale but nearly zero on oleander scale. In the laboratory H. coccophagus was reared continuously on the latania scale but failed to maintain itself on A. nerii. While developing on oleander scale, mites suffered high mortality and their generation time was twice as long as that on the latania scale.

The bodies of chaff scales, Parlatoria pergandii Comstock and P. cinerea Hadden, were larger on grapefruit than on orange; parasitization parameters on scales infesting the former host plant were higher than those on the latter.

The ability of H. coccophagus to parasitize and control pestiferous diaspidids may thus vary among host scales as well as their host plants. (L)

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Persistence of the Predatory Mite Hemisarcoptes coccophagus (Acari: Hemisarcoptidae) on Low Populations of Hemiberlesia lataniae

(Diaspididae) at a Site in New Zealand

John G. Charles, 1 M.G. Hill 2 and D.J. Allan 1 The Horticulture and Food Research Institute of New Zealand, Mt. Albert

Research Centre, Auckland, New Zealand; and llnternational Institute of Biological Control, Nairobi, Kenya

Population fluctuations of Hemisarcoptes coccophagus Meyer (Acari: Hemisarcoptidae) and Hemiberlesia lataniae (Signoret) (Diaspididae) on a row of shelter trees (lombardy poplar) have been measured, in the absence of any pesticide applications, since the initial establishment of the mite in New Zealand in January 1990. H. lataniae numbers declined from an average of about 50 adult females per 100 cm 2 of bark in January 1990 to fewer than 10 females per 100 cm 2 of bark in August 1990; this low level continued until December 1993. Adult scale parasitism by H. coccophagus peaked at 65% in May 1990 before slowly declining to 10% in November 1991; this level was sustained until December 1993. The mites were found on non-release-trees in the same row as the release-trees in April 1991, 16 months after initial establishment. This was despite the absence of Chilocorus spp. (Coleoptera: Coccinellidae), their phoretic partners. Although it is not known how the mites reached these trees, H. coccophagus deutonymphs have been found at other sites in New Zealand on ttalmus chalybeus (Boisduval) (Coccinellidae). Data are insufficient to determine if the diaspidid population decline was due to regulation by H. coccophagus, other natural enemies, or unrecognized biotic or abiotic factors. Nevertheless, the number of mites increased rapidly during the first few months of establishment, when the number of scale insects was high. The mites have subsequently persisted at low host densities on both the release-trees and non-release-trees for nearly 4 years since their introduction. (P)

Effect of Phenacoccus madeirensis Green (Pseudococcidae) on Some Biological Parameters of Four Species of Phytoseiid Mites

(Parasitiformes: Phytoseiidae)

Salvatore Ragusa di Chiara and H. Tsolakis 1st. di Entomologia Agraria, Universitd di Palermo, 90128 Palermo, Italy

The mealybug Phenacoccus madeirensis Green was supplied as prey to the following species of phytoseiid mites: Amblyseius stipulatus Athias-Hem'iot, Iphiseius degenerans Berlese, Typhlodromus exhilaratus Ragusa and Typhlodromus cryptus Athias-Henriot, to evaluate its effect on their postembryonic development and on the oviposition rate. None of the young stages of the four species developed to adults; they developed to larvae or protonymphs, but not a single deutonymph was obtained.

A list was given of the results obtained using other species of scale insects to show their suitability for the survival of predacious mites in the absence of optimal prey. (P)


Abstracts of papers presented at the 7th International Symposium of Scale Insect Studies (ISSIS-VII)

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Transcript of Abstracts of papers presented at the 7th International Symposium of Scale Insect Studies (ISSIS-VII)