Assignment Title:

Cruciferous pests, their taxonomic features, biology,nature of damage and management

Prepared By

Mr. Sushil Nyaupane

Exam Roll No. ENT-O5M-2013

Departmentof Entomology

Agriculture and Forestry University

Submitted to

Prof. Resham Bdr. Thapa

Departmentof Entomology

Agriculture andForestry University

Cruciferous Pest:

Crucifer is the very important vegetable in the world and inNepal also. The cultivation of this vegetable is large and isgradually increasing. Among the winter vegetables, cruciferousvegetables are the most important so the major insect pest ofcruciferous pests has special importance in the field of pestmanagement. The cruciferous crops (Brassica spp.) also known ascole crops and mainly consists of cabbage, cauliflower, broccoli,radish, turnip, carrot, Brussels sprouts etc. which have higheconomic and dietary value. Cabbage and cauliflower is cultivatedin around 27,445 ha. and 34,065 ha. with production andproductivity of 4,68,248 mt and 5,24,205 mt and 17.1 mt/ha and15.4 mt/ ha respectively(MOAD,2013).Here are some of the majorand minor pests of cruciferous groups of vegetables:

Major Pests:

1. Cababge butterfly(Pieris brassicae), Lepidoptera: Pieridae

2. Diamond back moth(Plutella xylostella), Lepidoptera: Plutellidae

3. Cabbage semi-looper(Plusia orichalcea), Lepidoptera:Noctuidae

4.Mustard aphid (Lipaphis erysimi) and Cabbage aphid(Brevicorynebrassicae);Homoptera:Aphididae

5. Tobacco caterpillar (Spodoptera litura); Lepidoptera;Noctuidae

Minor Pests:

1. Leaf webber (Crocidolomia binotalis): Lepidoptera; Pyralidae

2. Cabbage flea beetles (Phyllotreta cruciferae); Coleoptera; Chrysomelidae

3. Mustard saw fly (Athalia lugens proxima); Hymenoptera; Tenthredinidae

4. Painted bug (Bagrada cruciferarum); Hemiptera; Pentatomidae

5. Cutworms (Agrotis segetum); Lepidoptera; Noctuidae

6. Leaf miner (Phytomyza harticola); Diptera; Agromyzidae

Cabbage butterfly:

The cabbage butterfly is cosmopolitan in distribution and the major pest of the cruciferous vegetables like cabbage, cauliflower, knol-khol and some time it may also attack on turnip, radish, toria, sarson and other cruciferous pests.

Fig: Cabbage butterfly

Taxonomical features:

When full grown, they have length of about 40-50mm. The young larvae are pale yellow and become greenish

yellow later on. The head of cabbage butterfly is black and the dorsum is

marked with the black spots. The body is arranged with the short hairs. The butterflies are pale white and have a smoky shade on

the dorsal side of the body. The wings are pale white with a black patch on the apical

angle of each forewing and a black spot on the coastalmargin of each hind wing.

The females measure 6.5 cm across the spread wings andhave two conspicuous black circular dots on the dorsalside of each forewing.

Males are smaller than the females and have black spotson the underside of each forewing.

Biology:

Generally this pest appears on cruciferous vegetables at thebeginning of the October and remains active up to the end ofApril. From May to September, this pest is absent in the plainbut breeding takes place in the hilly region. The butterflies arevery active in the field and lay eggs on an average, 164yellowish conical eggs in clusters of 50-90 on the lower or theupper side of the cruciferous vegetables. Generally the eggshatch in 11-17 days in November- February and 3-7 days in March-May. The larvae feed gregariously during the early instars anddisperse as they approach maturity. They pass through five stagesand are full-fed in 15-22 days during March-April and 30-40 daysduring November-February. The larvae pupate at some distance fromthe food plants, often in barns or on trees. The pupal stagelasts for 7.7-14.4 days in March- April and 20-28 days inNovember- February. The butterflies live for 2.5-12.5 days andthe pest breeds four times during October- April. Apantelesglomeratus(L.)(Braconidae) generally parasitize the larvae ofthis insect.

Nature of Damage:

The caterpillars cause damage generally. The first instar larvaejust scrape the leaf surface, whereas the subsequent instars eatup leaves from the margins inwards, leaving intact the mainveins. The entire plants may be eaten up during the severe insectinfestation.

Management:

Handpicking and mechanical destruction of the caterpillars during the early stage of infestation can reduce the pest attack.

Spray 1 lit. of Malathion 50 EC in 250 lit. of water per ha at 10 days interval.

Follow field sanitation and remove the alternate hosts in the field.

Conservation of natural predators like Assasin bugs, Paper wasps.

Release of Trichogramma wasps, egg parasitoid of Cababge butterfly, inundative and augmentative release of larval parasitoids;Apanteles glomeratus.

Use cow urine in 1:7 in 1:7-10 ratio with water which has antifeedant or repellant in nature.

Use botanical materials like Garlic, Neem solution to repel or acting as antifeedant of caterpillars.

Spray commercial formulation of Bacillus thuringiensis i.e. Dipel@0.5g/lt. of water.

Diamondback moth

Diamond back moth is a serious pest of cauliflower and cabbage, but also feeds on many other cruciferous.

Taxonomical features

When fully grown, the larvae measure about the 8 mm in length.

Larvae are pale yellowish green with fine black hair scattered all over the body.

The moths measure about 8-12mm in length and are brown or grey, with conspicuous white spots on the fore wings, which appear like diamond patterns when the wings lie flat over the body.

The hind wings are white in color with fringes in apical margins.

Biology:

This insect is active throughout the year. Yellowish eggs of thesize of the pin-heads are laid singly or in batches of 2-40 on

the underside of leaves. One female can lay up to 18-365 eggs inher life time. The hatching takes place within 5 days and newlyhatched caterpillars bore in to the tissue from the underside ofleaves and feed in the tunnels. Larvae moult three times andcompletes larval period in 1-2 weeks, depending upon thetemperature and the availability of the food. The larvae are verysensitive to touch, wind or other physical disturbances andreally feign death. If disturbed, larvae wriggle backwardviolently and may drop from the plant and suspend by a silkenthread. After several seconds, the larva will climb back onto theleaf and continue feeding again. After one to two weeks, thecaterpillar pupates inside a gauze-like silken cocoon. Mothbecomes visible through the cocoon. The pupal stage lasts 5-15days, depending on environmental conditions. Normally, thediamondback moth takes about 32 days to complete its life cycle.

Management:

Practice deep summer ploughing, field sanitation andintercropping with tomatoes reduce pest infestation.

Use trap crops, mustard reduces its attacks; 15 rows ofcabbage followed by mustard row has been very effective toreduce pest population and crop damage.

Planting of Marigold also reduces the larval population upto30-50%.

Attract its adult mass population using DBM lure. Encourage natural enemies with plenty of breeding places;

the most important small wasp parasitoids are Diadegma,Apanteles and Diadromus.

Bacillus thuringiensis Berliner (Bt), a bacterium, iseffective against DBM.

Predators, such as Brown lacewing (Micromus tasmaniaeWalker), predacious bug(Nabis tasmanicus) and a range ofspiders and larva of Hover Flies feed on DBM eggs, larvaeand pupae.

Fig. Diamond back moth

3. Cababge semi-looper:

This is very widely distributed species and ployphagous infeeding habit. Cabbage semi-looper is the pest of cabbage,cauliflower and other winter vegetables. Cabbage semi-looper isthe phytophagous insect and attack a number of plants includinggroundnut and sunflower. The caterpillars are plump and palishgreen. Generally they cause damage by biting round holes intocabbage leaves. On walking, they form characteristic half-loopsand are often seen mixed with cabbage caterpillars.

Fig: Cabbage Semi-looper

Taxonomical features:

The adults of T. orichalcea are light palish brown with a large golden patch on each fore wing.

They measure about 42 mm across the spread wings. The adults of cabbage semi-looper are darker and have dark-

brown and dirty white patches on the fore wings.

Life Cycle:

These insects are active during the winter and it is not knownhow they survive the heat of the summer. During the activeperiod, they lay eggs on the leaves of the host plants and thecaterpillars feed individually, biting holes of varying sizeaccording to the stage of their development. When full-grown,they pupate in the debris lying on the ground. The moths are veryactive at dusk on flowers in gardens and public parks where theyare seen in hundreds during the spring season.

Management:

Handpicking and mechanical destruction of caterpillarsduring early stage of attack can reduce infestation.

Spray one litre of Malathion 50 EC in 250 litres of waterha. Repeat spraying at 10 day intervals if necessary. Do notspray the crop at least one week before the harvest.

Tobacco caterpillar:

The tobacco caterpillar is found throughout the tropical and sub-tropical parts of the world. It is very important pest for thecruciferous pests.

Fig: Tobacco caterpillar

Taxonomic features:

The damage is done by the caterpillars, which measure 35-40mm in length at maturity.

They are velvety black with yellowish-green dorsal stripesand lateral white bands.

The moths are about 22 mm long and measure 40 mm across thespread wings.

The fore wings have beautiful golden and greyish brownpatterns.

Life Cycle:

This pest breeds throughout the year, although its development isconsiderably retarded during the winter. The moths are active atnight generally when they mate and the female lays about 300 eggsin clusters. These clusters are covered by brown hair and theyhatch in about 3-5 days. The larvae feed gregariously for thefirst few days and then disperse to feed individually. They passthrough 6 stages and are full-fed in 15-30 days. The full grownlarvae enter the soil where they pupate. The pupal stage lasts 7-15 days and the moths, on emergence, live for 7-10 days. The lifecycle is completed in 32-60 days and the pest completes eightgenerations in a year.

Nature of damage:

The larvae feed on leaves and fresh growth. They are mostlyactive at night and cause extensive damage, particularly intobacco nurseries.

Management:

Remove the egg masses and clusters of larvae and destroythem.

Spray 750 ml of Dipel 8L or 750g of Halt WP (Bacillusthuringiensis var. kurstaki) in 200-250 ml of water in theevenings at one week interval.

Spray 625 ml of Spinosad 2.5 SC or 175 g emamectin benzoate0.58 G or 325 ml indoxacarb 15.8 EC or 500 g cartaphydrochloride 50 SP or quinalphos 35 EC or 250 ml offenvalerate 20 EC in 250 litres of water per ha. Repeatsprays after 10 days, if necessary.

Flea beetle:

Flea beetle; phyllotreta cruciferae Geoeze are the most commonpests of cruciferous crops and are characterized by enlarged hindfemora and well jumping behavior. Their host plants include

cabbage, turnip, cauliflower, Brussels sprouts, canola, tomatoes,radish, potatoes, wild mustard and other crucifers.

Fig. flea beetle

Taxonomic features:

The males are smaller than the females. The dorsum of the adult beetle, P. cruciferae, is metallic

blue in color with a greenish hue. The body is elongate narrow in front but broad distally and

the beetle is round at the anal end. The head is finely punctate and the antennae extend beyond

the middle of elytra. The female beetle measures 2.0 mm in length while the male

beetle measures 1.8 mm. The larva is dirty white in color with pale white head and

measures about 5 mm in length.

Biology:

This pest is active throughout the year except during the wintermonths, when it hibernates in the soil or among the plant debris.The over-wintered adult beetles emerge in the last week ofFebruary or in the beginning of March and settle on the growing

cruciferous plants. The female beetle lays 50-80 creamy whiteeggs singly in the soil around the host plants, during theoviposition period of 25-30 days. The incubation period rangesfrom between 5-10 days. The larva is very active and feeds on thetender roots of the tender roots of the host plants. It moultsthrice during a total larval period of 9-15 days. The larvabefore entering into the prepupal stage wriggles out of the minedroots and prepares an earthern cell, 0.5 mm long, in the vicinityof the infested plants. There it pupates. The pre-pupal period is2-4 days and the pupal stage lasts 8-14 days. There are 7-8generations of this pest in a year.

Nature of damage:

The adults mostly feed on the leaves by making innumerable roundholes in the host plants. The stem, the flowers and even pods mayalso be attacked. The old, eaten away leaves dry up, while theyoung leaves are rendered unfit for consumption. A special kindof decaying odour is emitted by the cabbage plants attacked bythis pest.

Management:

Practice field sanitation, deep ploughing and removal ofalternate hosts.

Predators known to feed on flea beetles include lacewinglarvae (Chrysoperla carnea Step.) and Big-eyed bugs(Geocoris bullatus Say).

Commercial formulation of Entomopathogenic Nematodes isuseful in reducing the flea beetle damage.

Organic growers can use Pyrethrin, Neem, Rotenone, or Hotpepper against the pest.

Use chemical pesticides like Malathion or Cypermethrin@ of2-3 ml/lit. of water with great care of flower visitors.

Mustard Aphid & Cabbage aphid

Aphids are very serious insect of vegetable crops. These aresoft-bodied insect with a posterior pair of tubes (cornicle orsiphunculi) which project upward or backward from dorsal surfaceof the abdomen and which are used for excreting a defensivefluid. They vary in color. Generally occur in colonies. Immatureare smaller than adults but similar in color and shape. Theyreproduce(oviparous) and parthenogenetically. Both adult andnymphs of aphids have piercing and-sucking type of mouth typewhich is used for feeding by sucking sap from the plant tissues.They pierce veins, stems and growing tips with their needle likemouth parts. Aphids also produce considerable quantity of honeydew which makes the plants sticky favoring the growth of sootymould as a result of which a black coating is formed on affectedplant parts, which hinders the photosynthesis process in plants.Heavily infested plants turn brown and die from the top to down.Newly grown plant parts become stunted and curled. They transmitvarious mosaics, leaf roll disease. They affect all plant growthstage as seedling, vegetative growth, flowering and fruitingstage. Thus, both nymphs and adults the quality and quantity ofcrop yield.

Cabbage aphid:

Taxonomic features:

They are 1.6-2.8 mm in body length. They have short siphunculi and triangular cauda. Their body is covered with greyish-white mealy wax.

Fig: Cabbage aphid

Mustard aphid

Fig: Mustardaphid

Taxonomical features:

Wingless mustard aphid is 1.4-2.4 mm in length. They are yellowish green, greyish green or blackish green

and lightly covered with the powder which forms a white waxbloom.

Winged female adults are 1.4- 2.2 mm in body length. They have dusky green abdomen with lateral stripes

separating the body segments and dusky wing vein. The head and thorax are black and the abdomen the green to

dark green.

Male aphid is olive-green to brown in color.

Biology:

Aphids reproduce very rapidly. Males are uncommon and femalesgive birth to live nymphs all year rather than mating and layingeggs. Nymphs mature in 7 to 10 days. When host plant qualitydeteriorates or if plants become overcrowded, winged formsdevelop and migrate to new host plants. Aphids have fine,piercing-sucking mouthparts and feed on plant sap. They are oftenprotected from their many natural enemies by ants, which feed ona sugary waste product of the aphids called honeydew. Aphids aremore abundant during the spring and fall and almost disappear insummer.

Nature of damage:

Aphid is a major pest of greens (collards, kale, and mustard), aswell as many other unrelated crops. They attack cabbage mainlybefore heading begins. Turnip aphids attack only crucifers,preferring turnips and radishes. Aphids suck plant juices withtheir piercing-sucking mouthparts, resulting in yellowing andcurling of the leaves. The plant, particularly when attacked as aseedling, may be stunted or die as a result of aphid feeding.Foliage may be contaminated with aphid bodies, cast skins, andhoneydew. Aphids can be protected from insecticide sprays withinthe curled leaves or inside the cupped leaves of headed plants.Green peach aphid and turnip aphid vector turnip mosaic virus.

Management:

Conservation and release of predatory insect such as thelady bird beetle.

Install yellow pan trap with 1% kerosene water or yellowsticky traps at crop height in the fields for monitoringoccurring of winged aphid.

Do not use excess amount of nitrogenous fertilizer. Dust wood ashes on the plant foliage in the morning hours.

Similarly dust red soil on plant foliage.

Spray neem based extracts and tobacco extract. Spray chemical pesticide like Malathion 50% EC 2ml or Rogor

30% EC @ 1ml/lit. of water.

References:

Atwal, A.S. (1976) “Agricultural pests of India and South EastAsia”, Kalyani Publishers, New Delhi, India, pp. 377-384.

Griffin RP, Williamson J. (2012). Cabbage, Broccoli & Other ColeCrop Insect Pests. HGIC 2203, Home & Garden InformationCenter. Clemson Cooperative Extension. Clemson University,Clemson, SC. (2 October 2013)

Neupane, F. P. (2000). Tarkaribali ma

lagnekiraharukayekikritbyabasthapan (In Nepali). Lalitpur, Nepal:

Centre for Environmental and Agricultural Policy Research,

Extension and Development.

Tiwari, S &Thapa, R.B., Laboratory manual of Economic entomology,Nepal, IAAS, Nepal