Agromyzidae) Resistance in Mungbean

Morphological and Physiological Traits Associated withAgromyzid (Diptera: Agromyzidae) Resistance in Mungbean

N. S. TALEKAR, HUI CHIN YANG, ANDYING HUE LEE

Asian Vegetable Research and Development Center, Shanhua, Tainan 74199,Taiwan, Republic of China

J. Econ. Entomol. 81(5): 1352-1358 (1988)ABSTRACT Morphological and physiological characters of three resistant and two suscep-tible mungbean accessions were studied to understand the nature of their resistance toagromyzid flies.The highly resistant accessionhad high trichome density on leavesand stems,purplish and smaller diameter sterns,and smaller unifoliate leaves. Agromyzid adults showedlower preference for visiting seedlings of resistant compared with susceptible accessionsforfeeding and oviposition,which were significantlypositively correlated with insect infestation.Pupation of the agromyzid was delayed when larvae were feeding inside stems of resistantcompared with susceptible accessions.Plant tissuesof resistant accessionsdamaged by agro-myzid feeding had significantly fewer larvae and pupae compared with similar tissues ofthe susceptible accessions. Larvae of Porthesia taiwana Shiraki and Heliothis armigeraHiibner had greater mortality and reduced pupation when fed unifoliate leaves of resistantcompared with susceptible mungbean accessions.Acombination of several characters appearsto be responsible for resistance.

KEY WORDS Insecta, resistance mechanism, preference, antibiosis

MUNGBEAN,Vigna radiata (L.) Wilczek, an im-portant pulse crop grown widely in South andSoutheast Asia, is infested by a diverse group ofinsect pests from germination to harvest and duringstorage. Among the first pests to infest the crop arethree fly species-the bean fly, Ophiomyia phaseoli(Tryon), O. centrosematis (de Meijere), and Me-lanagromyza sojae (Zehntner) (all Diptera: Agro-myzidae)-which feed within stems of mungbeanseedlings almost throughout the year (Talekar &Chen 1983). If the agromyzids are not controlledin time, crop losses of up to 100% can be expected,especially in the more tropical areas of SoutheastAsia.

To develop effective and environmentally lessdamaging control measures, research efforts at theAsian Vegetable Research and Development Cen-ter (AVRDC) in Taiwan are directed toward de-veloping mungbean cultivars resistant to agromy-zids. In this respect, screening of 3,713 accessionsbetween 1976 and 1979 resulted in identificationof three accessions showing moderate to high levelsof resistance to agromyzids (Chiang & Talekar1980). All three accessions come from India. Theyare late-maturing and have small seeds and lowyield potential. In addition, the accession with thehighest level of resistance, AVRDC accession V4281,has black, mottled seeds which are unacceptablefor commercial cultivation. Therefore, these resis-tant accessions, especially V4281, are being usedto breed agronomic cultivars of mungbean resistantto agromyzids (AVRDC 1984) at AVRDC. Thepurpose of this study was to understand the mech-anism of resistance in three agromyzid-resistantmungbean accessions to facilitate the breeding pro-

gram. Here we report the results of research de-signed to identify the major morphological, phys-iological, and insect preference characters thatdistinguish resistant from susceptible accessions.

Materials and Methods

Plant Morphology. Three agromyzid-resistantand two susceptible mungbean accessions weregrown in the field in autumn. Land was rototilledand worked into 0.75-m beds which were parti-tioned into plots (5 by 3 m). Seeds of each accessionwere planted in four randomly selected plots; eachplot represented one replicate. These plots werearranged in a randomized complete block design.The crop was raised by customary cultural prac-tices except that insecticides were not used. At pre-determined intervals within the first 5 wk afteremergence (WAE), 10 plants were uprooted fromeach plot for the study of various morphologicalcharacteristics.

Leaves. At about 4 WAE, unifoliate and the firsttwo trifoliate leaves were studied for leaf area,trichome density, leaf thickness, dry matter, andmoisture content. Length and thickness of petiolesof trifoliate leaves were also studied.

Leaf Area. Ten unifoliate and 10 first trifoliateleaflets from plants in each replicate were sampled,and their total leaf areas were measured by a leafarea meter (Li-Cor Corporation, Lincoln, Nebr.).The length and diameter of the petioles of each ofthe 10 trifoliate leaves also were measured.

Trichome Density. From each replicate, 10 uni-foliate and 10 newly opened first trifoliate leafletswere sampled. The number of trichomes was re-

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October 1988 TALEKAR ET AL.: AGROMYZID RESISTANCE IN MUNGBEAN 1353

Table 1. Unifoliale and trifoliale leaf characleristics ofagromyzid-resislanla and susceptible mungbean accessions

Table 3. Characterislics of siems of agromyzid-resis-lanla and susceptihle mungbean accessions

Area (cm2) per leaf Petiole Stem thickness

Accessionb Unifo- Trifo- Thick-(mm) between

Length Accessionsb No. trichomes perliate liate ness (em) em length of stem at" Cotyledon Unifoliate

leaves leaves (mm) to to first

V2396 (MR) 4.17c 125c 1.98b 9.97b3WAE 5 WAE unifoliate trifoliate

V3495 (MR) 4.llc llOc 2.06b 8.97b V2396 (MR) 11.00b 9.30b 3.5Oc 4.01bV4281 (HR) 4.41c l09c 1.86b 8.85b V3495 (MR) 10.75b 6.05c 3.64bc 3.92bV2184 (S) 9.31a 199a 2.43a 12.15a V4281 (HR) 24.40a 23.70a 3.32c 3.72bV3428 (S) 7.24b 161b 2.30a 1l.60a V2184 (S) 2.65c 3.50cd 4.58a 4.95a

V3428 (S) 5.60c 2.60d 3.96b 4.61aFirst trifoliate leaf petiole. Data are means of four replicates.

Means in e~ch vertical column followed by the same letter arenot significantly different (P = 0.05; Duncan's [1955] multiplerange test).

a Ophiomyia phaseoli, O. centrosematis, and Melanagromyzasotae.

MR, moderately resistant; HR, highly resistant; S, susceptible.

corded in three areas (5 by 5 mm) in the leaflamina, excluding major veins, on upper and lowersides of each leaflet.

Leaf Thickness. Ten unifoliate and 10 first twotrifoliate leaflets (newly opened) were sampled fromeach replicate. The thickness of leaf lamina of eachleaflet was measured with a micrometer at threepoints, carefully avoiding the major veins.

Leaf Dry Weight and Moisture Content. Twen-ty unifoliate and 20 first two trifoliate leaflets weresampled from each replicate. After fresh weightswere recorded, the leaflets were dried at llo·e for24 h, and dry weights were recorded. The moisturecontent was determined by subtracting the dryweight from the fresh weight.

Stem Trichome Density. Five plants were sam-pled in each replicate, and the number of trichomeswas recorded in three l-cm linear areas, startingfrom the hypocotyl, along the circumference ofthe stem.

Stem Diameter. The plants that were sampledfor trichome density were used for stem diametermeasurements. The diameter of each plant stemwas measured with a micrometer at internodes be-

Data are means of four replicates. Means in each vertical columnfollowed by the same letters are not significantly different (P =0.05; Duncan's [1955] multiple range test).

a Ophiomyia phaseoli, O. centrosematis, and Me/anagromyzasotae.

MR, moderately resistant; HR, highly resistant; S, susceptible.C W AE, weeks after emergence of mungbeans.

tween cotyledon and unifoliate leaf and unifoliateleaf and the first trifoliate leaf.

Stem Moisture Content. Ten plants were sam-pled from each replicate. After stripping off thefoliage and cutting out the roots, the stems wereweighed. The stems were dried at llo·e for 24 hand the dry weights were recorded. The moisturecontent was calculated as the difference betweenfresh and dry weights.

In addition to the preceding observations, thelengths of the first and second internodes on thestem were measured, and the color of the stem inthis region and the hypocotyl was recorded.

Adult Preference. Seeds of three resistant andtwo susceptible accessions were planted three timesin the field during the autumn of 1982. Each acces-sion was planted as a single row on top of the threerandomly selected beds (1 m long, 0.75 m wide).Soon after germination, once every morning foreight consecutive days, the number of agromyzidfliessitting on the unifoliate leaves of each accessionin each plot was recorded. Mean numbers of adultsvisiting the plants at every observation for all three

Table 2. Trichome densily on the leaf surfp.ces of agromyzid-resistant" and susceptible mungbean accessions

No. trichomes per 25-mm2 leaf surface<

Unifoliate leaves Trifoliate leavesAccessionb

Upper surface Lower surface Upper surface Lower surface

1 WAE 3WAE 1 WAE 3 WAE 2WAE 3 WAE 2WAE 3 WAE

V2396 (MR) 2.08b 8.57b 0.08 0.09b 8.78b 10.27b 4.46b 2.71bV3495 (MR) 0.25b 7.08c 0.00 O.OOb 9.63b 1O.39b 1.21bc 0.88cV4281 (HR) 14.84a ll.29a 1.58 4.83a 38.22a 56.40a 8.66a 5.83aV2184 (S) 0.25b 7.02c 0.00 O.OOb 6.56b 4.58b 1.14bc 0.55cV3428 (S) 0.08b 8.91b 0.50 o.oOb 5.16b 5.45b 0.39c 0.40c

Data are means of four replicates. Means in each vertical column followed by the same letter are not significantly different (P =0.05; Duncan's [1955] multiple range test).

a Ophiomyia phaseo/i, O. centrosematis, and Melanagromyza sojae.b MR, moderately resistant; HR, highly resistant; S, susceptible accessions.C Only the leaf lamina was examined; midrib and main veins were not included. WAE, weeks after emergence of mungbean.

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1354 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 81, no. 5

Table 4. Agromyzida adult feeding and ovipositionpunclure counls in unifoliale leaves of resistant and sus-ceplible mungbean accessions

AccessionsbNo. punctures per uni£oliate leaf at"

1 WAE 2WAE 3WAE

V2396 (MR) 2.02a 0.78b 0.66bV3495 (MR) 3.75a 1.64b 1.07bV4281 (HR) 1.75a 0.87b 0.69bV2184 (5) 4.44a 3.57a 2.62aV3428 (5) 3.97a 1.45b 2.73a

80

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aab !Wi

.~::t:f::;

~~~1~~~~~:l:jljllllj:.~~Ij~~~~l m~mm;~......!j:j~~~!::111jl~~11j c c Ij~!~1~~:$:: Ii~:i::n

illllllill :1111

111:j~~~~~~~j~~~

~~~~~1~[~!liljij!l!l .~][~[~~Data are means of four replicates; each replicate had 10 leaflets.

Means in each vertical column followed by the same leller arenot significantly different (P = 0.05; Duncan's [1955] multiplerange test).

a Ophiomyia phaseoli and Melanagromyza sojae,b MR, moderately resistant; HR, highly resistant; S, susceptible.C W AE, weeks after emergence of mungbean accessions.

plantings were computed. When the plants were4 wk old, 10 plants from each replicate were up-rooted, and their stems were dissected to observeagromyzid infestation. The number of agromyzidlarvae and pupae found within each plant stem,and the number of plants with visible insect dam-age, were recorded. The data on the number ofadults visiting the plants and the number of larvaeand pupae found within the stems were analyzedby simple linear regression and correlation (Little& Hills 1975) between the agromyzid adults vis-iting the unifoliate leaves and the infestation asjudged by the number of agromyzid larvae andpupae in the stems.

The plants that were grown for observations ontrichome density also were observed for food andoviposition punctures. When plants were 1, 2, and3 wk old, 10 unifoliate leaves from each replicatewere observed for food and oviposition puncturesmade by the agromyzid adults. Because of the iden-tical shape and size of the food and ovipositionpunctures and transparent nature of agromyzid eggs(making it difficult to observe them in puncturedleaf tissue) no distinction was made between foodand oviposition punctures. The total number ofpunctures in each unifoliate leaflet was recorded.

Antibiosis. Seeds of three resistant and one sus-ceptible mungbean accessions were planted in thefield four times, once each in July, August, Sep-tember, and October 1985. Each entry was plantedas a single row on top of each of the four randomlyselected beds (10 by 0.75 m). The crop was raisedby customary cultural practices except that no in-secticide was applied. At 5 WAE, 100 plants wereuprooted from each plot and dissected to observeagromyzid larvae, pupae, and damage. The num-ber of larvae and pupae and the number of dam-aged plants in each sample were recorded.

Three resistant and two susceptible mungbeanaccessions were grown in seedling flats containingsoil and compost mixture and placed in the green-house. Several flats were planted to each accessionweekly to provide a fresh supply of unifoliate leavesfor the insect feeding study.

V2396 V3495 V4281 V2184 V3428Accessions

Fig. 1. Frequency of agromyzid adults visiting uni-foliate leaves of various mungbean accessions.The sameletter at the top of each bar, representing the accession,indicates no significant difference (P = 0.05, Duncan's[1955] multiple range test).

Colonies of two polyphagous insects, POTthesiataiwana Shiraki (Lepidoptera: Liparidae) and He-liothis armigera Hiibner (Lepidoptera: Noctui-dae), were maintained on soybean foliage and onartificial diet, respectively, in the laboratory. Twounifoliate leaves of each accession were placed onmoist filter paper in each of five Petri dishes, and4 to 10 first instars of either P. taiwana or H.armigera were released on the leaves. Each Petridish represented one replicate. Petri dishes wereheld at 25°C and 65% RH. The insects were ob-served once a day for their feeding activity, andthe leaves were replaced at intervals to sustain lar-val feeding until pupation. At each observation,the number of living and dead larvae and the rateof pupation (the number pupated in each replicate)were also recorded.

All data on plant morphological characters, adultpreference, agromyzid fly infestation characteris-tics, and antibiosis were analyzed by analysis ofvariance. Means among the treatments were sep-arated using Duncan's (1955) multiple range testat P = 0.05.

Results

Plant Morphology. Results of the measurementsof leaf area and petiole dimensions are summarizedin Table 1. All three resistant accessions had sig-nificantly smaller unifoliate and first two trifoliateleaves. The petioles of the first trifoliate leaves weresignificantly shorter and thinner in all three agro-myzid-resistant entries compared with those of thesusceptible check accessions.

Unifoliate and trifoliate leaves of the highly re-sistant accession (V4281) had significantly highertrichome density on the upper surface at 1 W AEand 3 W AE (Table 2). Trichome density on lowerleaf surfaces of V4281 was also significantly higher,except on the unifoliate leaves at 1 W AE. Therewas no significant difference in trichome densitybetween the two moderately resistant accessionsand the susceptible check, except for V2396 on the

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October 1988 TALEKAR ET AL.: ACROMYZID RESISTANCE IN MUNCBEAN 1355

• •

~ 20cca. 15oN~ 10Q)

5

o

•

r=0.72**

6 10 14No. larvae + pupne/20 plants

r = 0.73**

50 70 90Damaged ptants (0/0)

Fig. 2. Relationship of frequency of agromyzid adults visiting unifoliate leaves and presence of their larvaeand pupae in plant stem as well as percent plants showing agromyzid damage .•• , correlation coefficient significantat P < 0.01 (Little & Hills 1975).

Insect status

Table 5. Characteristics of agromyzid fly" infestationin resistant and susceptible mungbean accessions at 5 wkofter germination

Data are means of four replicates and four monthly plantings.Means in each vertical column followed by the same letter arenot significantly different (P = 0.05; Duncan's [1955] multiplerange test).

a Ophtomyta phaseo/t, O. centrosemaHs, and Me/anagromyzasOlae.

MR, moderately resistant;HR, highly resistant;S, susceptible.

V2184

aIIIIIIII 0.phaseoliIIIIIIIII 0. cenfrosemafisGl] Msojae

o

en 15CoCi. 5 WAEoo:;;::~ 10a.::Ja..-0coQ)

~ 5•..o..JciZ

V2396 V3495 V4281Mungbean Accessions

Fig. 3. Distribution of immature stages of threeagromyzid species present in the stems of resistant andsusceptible mungbean accessions. For a given species,the same letter at the top of each bar indicates no sig-nificant difference (P = 0.05, Duncan's [1955] multiplerange test).

ceptible accessions (Fig. 1). Unifoliate leaves ofresistant accessions had significantly fewer punc-tures at 2 W AE and 3 W AE than their counterpartsin susceptible accessions (Table 4). A highly sig-nificant (P < 0.01) positive correlation was foundbetween the number of adults visiting the unifoli-ate leaves, the number of larvae and pupae foundin the stems, and the percentage of plants damagedby agromyzid larvae (Fig. 2). The moisture anddry-matter content varied among the five acces-sions, but there was no consistent pattern amongthe agromyzid-susceptible and resistant accessions.

Antibiosis Study. At 5 WAE, the number ofagromyzid larvae and pupae and the percentageof plants damaged by their infestation were sig-nificantly lower in resistant than in susceptibleaccessions (Table 5). The species composition ofagromyzids attacking resistant and susceptible

No. Damaged plants (%)larvae

and pupae Pupation Withper 100 % Total insectsplants present

7.8b 47.8ab 37.6b 7.7b7.3b 32.lbc 35.5bc 7.5b7.0b 25.5c 30.4c 6.6b

24.4a 59.6a 65.7a 22.9a

V2396(MR)V3495(MR)V4281(HR)V2184(S)

Accessionb

lower surface of trifoliate leaves at 3 W AE. Un i-foliate leaf thickness did not differ significantlybetween the resistant and susceptible accessions.

The trichome density on the stems of agromyzid-resistant accessions was significantly greater thanon the stems of susceptible accessions (Table 3).Among the resistant accessions, the higher the levelof resistance, the higher the trichome density. Thestems of resistant accessions also had significantlysmaller diameters than those of agromyzid-suscep-tible accessions. Among the resistant entries, V4281had the smallest stem diameter. The first and sec-ond internodes were shorter in resistant than insusceptible mungbean accessions. A significant pos-itive correlation was found between the numberof larvae and pupae in the stem and the length ofthe first (r = 0.73; df = 13; P < 0.01) and second(r = 0.72; df = 13; P < 0.01) internodes.

Adult Preference. The number of adults visitingfor oviposition or feeding on V 4281 and V3495 wassignificantly lower than the number visiting sus-

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Discussion

accessions had a significantly lower rate of pupa-tion. Similar larval mortality trends were observedin H. armigera that were fed unifoliate leaves ofresistant and susceptible accessions (Fig. 5). On tworesistant accessions (V3495 and V4281) the insectmortality increased rather abruptly just before pu-pation.

50

o100

Distinct differences in plant morphology, agro-myzid preference, and insect development char-acters were observed between agromyzid-resistantand susceptible mungbean. Because very little ba-sic information exists on the agromyzid-host plantinteraction, the herbivore-host plant relationshipinformation for other insects can be inferred tounderstand the observed differences in agromyzid-resistant and susceptible mungbean.

Ophiomyia phaseoli and M. sojae prefer newlyopened mungbean leaves for oviposition and feed-ing (van der Goot 1930). The female agromyzidpunctures leaf tissue with her ovipositor near majorveins (Spencer 1973) to lay eggs and feed on thesap oozing from the punctures. When population

Fig. 5. Development and mortality of H. armigeralarvae fed unifoliate leaves of agromyzid-resistant andsusceptible mungbean accessions.

V2184

60

o

accessions is shown in Fig. 3. The number of larvaeand pupae of O. phaseoli was significantly less inresistant accessions than in the susceptible check.A similar pattern existed in the case of O. centro-sematis, although the difference was not signifi-cant. The population of M. sojae was too low forvalid statistical comparisons, but resistant entrieshad lower numbers of larvae and pupae than thesusceptible accession.

Resistant accessions had significantly fewer plantsdamaged and significantly fewer insects present intheir damaged tissue than the susceptible checks.In resistant accessions, especially the highly resis-tant V4281, significantly fewer larvae pupated suc-cessfully (Table 5). The percentage of insects be-coming pupae in two moderately resistant accessionswas also lower compared with the susceptible check.In both cortex-feeding Ophiomyia species, percentpupation was considerably reduced when the in-sects were feeding inside two resistant accessions(V3495 and V4281) (Fig. 4). The pupation rate ofonly O. centrosematis was reduced in V2396.

Mortality of P. taiwana larvae fed unifoliateleaves of the resistant accessions, especially highlyresistant V4281, was significantly greater than thatof larvae fed on two susceptible checks (Table 6).The mortality rate in V4281 increased abruptlybetween 10 and 15 d of feeding. The percentageof larvae that pupated was greatly influenced bythe larval food source. Those that fed on resistant

.•...og- 20

CL

V2396 V3495 V4281Mungbeon Acc~ssions

Fig. 4. Pupation of two agromyzid species withinthe stems of resistant and susceptible mungbean acces-sions.

-0~ 40co

Table 6. Mortalityand pupation of P. taiwana larvae fed agromyzid-resistant"and susceptiblemungbean accessions

AccessionsbCumulativemortality,(%) at daysafterhatching Pupation

5 10 15 20 25 30 %

V2396(MR) 0.0 12.5 23,8b 38.3b 56.3b 59.3ab 3.3bV3495(MR) 2.5 9.0 15.3b 33.3b 54.5a 66.5ab O.ObV4281(HR) 12.5 22.5 69.5a 74.5a 74.5a 74.5a O.ObV2184(5) 8.3 12.5 12.5b 12.5b 21.8b 37.5b 24.8aV3428(5) 0.0 0.0 1O.Ob 16.3b 24.5b 44.0b 30.0a

Dataare meansof fivereplicates.Meansin eachverticalcolumnfollowedby the sameletterare notsignificantlydifferent(P =0.05;Duncan's[1955]multiplerangetest).

a Ophiom!l/a phaseoli, O. cenlrosemalis, and Melanagrom!lza sojae.b MR,moderatelyresistant;HR,highlyresistant;5,susceptible.

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October 1988 TALEKAR ET AL.: AGROMYZID RESISTANCE IN MUNGBEAN 1357

density is high, as during autumn in Taiwan (Tale-kar & Chen 1983), oviposition can take place any-where on the leaf lamina. Under such circum-stances, smaller unjfoliate leaves of resistantmungbean accessions offered limited leaf area onwhich adults could alight for feeding or oviposition.Chiang & Norris (1983a) in soybean and Mushe-bezy & Karel (1985) in snapbean, Phaseolus vul-garis L., also found significantly smaller unifoliateand early trifoliate leaves in agromyzid-resistantthan in susceptible accessions. After mining the leaflamina, agromyzid larvae burrow through the pet-iole to enter the stem for feeding and pupation.The smaller diameter of agromyzid-resistantmungbean petioles would restrict tunnelling in thecortex by O. phaseoli and in pith by M. sojae, thusreducing the number of larvae entering the stem.

Lin (1979) showed a negative correlation be-tween trichome density on the leaves of adzukibean, Vigna angularis (Willd.) Ohwi and Ohashi;blackgram, Vigna mungo (L.) Hepper; cowpea,Vigna unguiculata (L.) Walp; mungbean; rice-bean, Vigna umbellata (Thunb.) Ohwi and Ohashi;and snapbean and numbers of O. phaseoli larvaeand pupae in stems. In our study, the greater tri-chome density on the unifoliate and early trifoliateleaves of the highly resistant accession V4281 prob-ably contributed to reduced oviposition becauseoviposition-feeding punctures were fewer on thefoliage of V4281; this probably contributed to thereduction in infestation.

Past reports stated that O. centrosematis hiyseggs in leaves (Lee 1976). This report was cited byChiang & Norris (1983a) to explain the role oftrichomes on the foliage in the resistance of Glycinesoja Sieb and Zuec to agromyzids. However, ourrepeated observations in mungbean and soybeanshowed that species to lay eggs only in the hypo-cotyl of young seedlings (unpublished data). Sim-ilar observations were recorded by Greathead (1968)with snapbean in East Africa. High trichome den-sity on stems and smaller stem diameter, especiallythat of V4281, probably interfered with the ovi-position of O. centrosematis and reduced its in-festation.

The distinctly purple stem of resistant mung-bean, especially V4281 (similar to the O. centro-sematis-resistant wild soybean [Chiang & Norris1984]), probably resulted in reduced infestation ofthis mungbean accession by the agromyzids. In anearlier study, analysis of the stem cortex of V4281and an accession of Vigna glabrescens (Roxb.)Verdc. (a close relative of mungbean which is high-ly resistant to agromyzids) showed 0.51 and 0.50mg phenolic compounds per gram of cortex tissue(dry weight basis), respectively, compared with 0.06mg/g in V2184 (AVRDC 1984). Phenolic com-pounds are reportedly involved in the protectionof plants against many herbivores (Feeny 1970,Beck & Reese 1975, Reese 1977), including agro-myzids (Chiang & Norris 1983b).

Because first instars of O. phaseoli and M. sojae

feed in the leaves until molting, the unifoliate leaves(the first to be exposed to agromyzids) play animportant role in agromyzid infestation. The pres-ence of unfavorable nutritional or toxic factors inthis part of the plant will have a bearing on pestinfestation. Since it is impossible to force feed theagromyzid larvae by taking them out from the hostand placing them inside the foliage of another plantto observe the effects on growth and development,two polyphagous pest lepidoptera, P. taiwana andH. armigera, were used to assess the level of an-tibiosis in the foliage of the agromyzid-resistantmungbean. The higher the level of resistance toagromyzids, the greater was the mortality of P.taiwana and H. armigera. Failure of P. taiwanato pupate or the rapid mortality of H. armigerajust before pupation when fed V3495 and V4281indicate the toxic effects of certain principles (orabsence of essential chemicals) in the foliage ofthese accessions. This adverse effect probably re-duces significantly the number of agromyzid larvaebefore they can enter the stem.

By demonstrating the antibiosis of agromyzid-resistant accessions to P. taiwan a and H. armigera,we do not imply that the nutritional or develop-mental physiology of the agromyzids and these twolepidopterans is identical. However, the antibiosisfactors in agromyzid-resistant accessions appear tobe of a general nature. This is further confirmedby the fact that the agromyzid-resistant V4281 alsoshows a moderate level of resistance to a foliardisease, powdery mildew, caused by the fungusErysiphe polygoni DC (AVRDC, unpublished data).

Several morphological and biochemical factorsseem to be associated with resistance to agromyzidsin mungbean, suggesting that the resistance is poly-genic. This observation was confirmed by Dista-banjong & Srinives (1985), who used V4281 to breedagromyzid resistance with local mungbean in Thai-land.

Acknowledgment

This report is a contribution of the Asian VegetableResearch and Development Center (AVRDC). This isAVRDC Journal Paper No. 100.

References Cited

AVRDC. 1984. Progress report 1982. Asian VegetableResearch and Development Center, Shanhua, Tai-wan, Republic of China.

Beck, S. D. & J. c. Reese. 1975. Insect-plant inter-actions: nutrition and metabolism, pp. 41-92. In 1.W. Wallace & R. L. Mansell [eds.], Biochemical in-teraction between plants and insects. Plenum, NewYork.

Chiang, H. S. & D. M. Norris. 1983a. Morphologicaland physiological parameters of soybean resistanceto agromyzid beanflies. Environ. Entomol. 12: 260-265.

1983b. Phenolic and tannin contents as related toanatomical parameters of soybean resistance to agro-myzid bean flies.1. Agr. Food Chern. 31: 726-730.

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1984. "Purple stem," a new indicator of soybean stemresistance to bean flies (Diptera: Agromyzidae). J.Econ. Entomol. 77: 121-125.

Chiang, H. S. & N. S. Talekar. 1980. Identificationof sources of resistance to beanfly and two other agro-myzid flies in soybean and mungbean. J. Econ. Ento-mol. 73: 197-199.

Dislabanjong, K. & P. Srinives. 1985. Inheritance ofbeanfly resistance in mungbean (Vigna radiata (L.)Wilczek). Kasetsart J. (Nat. ScL) 19: 75-84.

Duncan, D. B. 1955. Multiple range and multiple Ftests. Biometrics 11: 1-42.

Feeny, P. 1970. Seasonal changes in oak leaf tanninsand nutrients as a cause of spring feeding by wintermoth caterpillars. Ecology 51: 565-581.

Greathead, D. J. 1968. A study in East Africa ofbeanflies (Dipt., Agromyzidae) affecting Phaseolusvulgaris and their natural enemies, with the descrip-tion of new species of Melanagromyza Hend. Bull.Entomol. Res. 59: 541-561.

Lee, S. Y. 1976. Notes on some agromyzid flies de-structive to soybeans in Taiwan. Formosan Sci. 30:54-62.

Lin, C. S. 1979. Varietal resistance of mungbean tothe beanfly and the other agromyzids. Ph.D. disser-tation, University of Hawaii, Honolulu.

Little, T. M. & F. J. Hills. 1975. Statistical methodsin agricultural research. Little & Hills, University ofCalifornia, Davis.

Mushebezy, D. M. K. & A. K. Karel. 1985. Resistanceto bean fly (Ophiomyia phaseoli Tryon) in commonbeans, pp. 62-68. In A. N. Minjas & M. P. Salema[eds.], Proceedings of the fourth workshop on beanresearch in Tanzania. Sokoine University of Agricul-ture, Morogoro, Tanzania.

Reese, J. C. 1977. The effects of plant biochemicalson insect growth and nutritional physiology, pp. 129-152. In P. A. Hedin [ed.], Host plant resistance topests. American Chemical Society, Washington.

Spencer, K. A. 1973. Agromyzidae (Diptera) of eco-nomic importance. Junk, The Hague.

Talekar, N. S. & B. S. Chen. 1983. Seasonality ofinsect pests of soybean and mungbean in Taiwan. J.Econ. Entomol. 76: 34-37.

van der Goot, P. 1930. Agromyzid fliesof some nativelegume crops in Java. Tropical Vegetable Informa-tion Service, Asian Vegetable Research and Devel-opment Center. Shanhua, Taiwan, ROC (translationfrom Dutch).

Received for publication 18 May 1987; accepted 10May 1988.

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Agromyzidae) Resistance in Mungbean

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