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INSECT PESTS OF CUCURBITS R. Regmi Assistant professor Department of entomology

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Page 1: Insect pests of cucurbits


R. RegmiAssistant professor

Department of entomology

Page 2: Insect pests of cucurbits

Insect pests of cucurbits

Major insect pests• Red Pumpkin Beetle, Aulacophora foveicollis (Coleoptera:


• Cucurbits Stink Bug, Cordius janus (Hemiptera: Pentatomidae)

• Pumpkin Fruit Fly, Bactrocera curcubitae (Diptera: Tephritidae)

• Spotted Beetle, Epilachna vigintioctopunctata / E. Pussillanima (Coleoptera: Coccinellidae)

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Red pumpkin beetle Cucurbit stink bug

Spotted beetle, Epilachna beetle Cucurbit fruit fly

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Minor insect pests• Cutworm, Agrotis segetum/A. ipsilon (Lepidoptera: Noctuidae)

• Flea Beetle, Phyllotreta crucifera (Coleoptera: Chrysomelidae)

• Aphids, Aphis gossypii/ Myzus persicae (Homoptera: Aphididae)

• Whitefly, Bemisia tabaci (Homoptera: Aleyrodidae)

• Soybean Hairy Caterpillar, Spilarctia casigneta (Lepidoptera: Arctiidae)

• Banded Blister Beetle, Mylabris orientalis (Coleoptera: Meloidae)

• Semilooper, Anadividia (Phytometra) peponis (Lepidoptera: Noctuidae)

• Stem Boring Beetle, Apomecyna saltator (Coleoptera: Cerambicidae)

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Cutworm ` Flea beetle

White fly Peach aphid Banded blister beetle

Stem boring beetle

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Soybean hairy catterpillar

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Red Pumpkin Beetle, Aulacophora foveicollis (Coleoptera:

Chrysomelidae)• Red pumpkin is serious pest of cucurbits which is widely distributed in Asia,

Australia, southern Europe and Africa.

• Damage is caused by grubs as well as by beetles.

• The grubs lead a subterranean(underground) life and, full grown grub measure about 12 mm in length and 3.5 mm across the mesothorax.

• They are creamy white, with a slightly darker oval shield at the back.

• The beetles feed on above the ground plant parts. They are oblong and 5-8mm long.

• Their dorsal body surface is brilliant orange red & ventral surface is black being clothed in short white hair.

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Life cycle: • The beetles are found concealed in groups under dry weeds, bushes & plant remains

or in the cervices of soil.

• They resume activity as soon as the season warms up

• In life span of 60-85 days, lay about 300 oval yellow eggs singly or in batches of 8-9 in moist soil, near the base of the plants.

• The eggs hatch in 6-15 days and the grubs remain below the soil surface feeding on roots, underground stems of creepers and on fruits laying in contact with the soil.

• They are full grown in 13-25 days and pupate in thick walled earthen chambers in the soil, at a depth of about 20-25 cm.

• The pupal stage lasts 7-17 days and the beetles, on emergence, begin to feed and breed.

• The life cycle is completed in 26-37 days and the pest breeds five times from March to October.

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Damage: • The beetles are very destructive to cucurbitaceous vegetables,

particularly during March-April when the creepers are very young.

• The grubs damage the plants by boring into the roots, underground stems & sometimes into the fruits touching the soil.

• The beetles injure the cotyledons, flowers and foliage by biting holes into them.

• The early sown cucurbits are to severely damage.

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• Infested fields plough deep to kill the grubs in the soil.

• Flooding irrigation in the field.

• Sow the crop in November to avoid damage by this pest

• Apply 7Kg of carbofuran 3G per ha 3-4 cm deep in the soil near the base of the plants just after germination and irrigate.

• Spray 375g of Carbaryl 50WP in 250 liters of water per ha

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Cucurbits Stink Bug, Cordius janus (Hemiptera: Pentatomidae)

• The cucurbits stink bugs attack all members of the cucurbits.

• Adults are winged and grayish brown.

• The edges of the abdomen and underside of the insect have orange to orange brown stripes.

• Feeding by piercing and sucking mouthparts occurs primarily on the plant foliage and tender stems.

• Sometimes, cucurbits stink bugs may also damage on fruits.

• The associated damage symptoms include wilting of leaves and ultimately result black or dry out.

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Life Cycle: • Cucurbits stink bug egg are 1/16 inch long & laid in clusters of 15-40 on

the undersides of leaves or stems.

• Eggs are bronze to brick red in color and hatch in 1 to 2 weeks.

• The colour of nymph ranges from mottled white to greenish gray, which have black legs.

• Later on, they turn dark brown & resemble with adults.

• The nymphs have partial development of wings, whereas the adults have full-grown wings.

• The nymph become adult in 4 weeks.

• The total life cycle completes within 4-5 weeks.

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Management: • Collect and destroy the different stages of bug.

• Field sanitation, removal of weed hosts and other overwintering sites of bugs.

• Parasitiod like a Tachinid fly (attack nymph and adult) and some wasps (Hymenoptera: Encyrtidae and Scelionidae are egg parasition) can be used for management.

• Spray 1 liter of malathion 50EC in 250 liters of water per ha.

• Spray Rogor (dimethoate) 30 EC @1ml/liter of water.

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Pumpkin Fruit Fly, Bactrocera curcubitae (Diptera: Tephritidae)

• This is the most destructive pest of cucurbits.

• Only the maggot cause damage by feeding on near ripe fruits, riddling (piercing ) them and polluting the pulp.

• The maggots are legless and appear as headless, dirty white wriggling creatures, thicker at one end and tapering to a point at the other.

• A full grown maggot is 9-10 mm long & 2 mm broad in the middle.

• The adult flies are reddish brown with lemon yellow markings on the thorax and have fuscous areas on the outer margin of their wings.

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Life cycle• This pest is active throughout the year, but the life cycle is prolonged during winter.

• The adult flies emerge form pupae in the morning hours and mate at dusk.

• It takes a few days for the eggs to mature inside the body of female which starts laying them within 14 days.

• During winter, the pre-oviposition period is prolonged.

• They oviposit in comparatively soft fruits avoiding those with hard rind.

• The selection of a suitable sites and the actual laying of eggs take about 6-8 minutes.

• A cavity is made by sharp ovipositor and about a dozen white cylindrical egg are laid, mostly in the evening hours.

• After laying the eggs, the female releases a gummy secretion which cements the tissues surrounding the pucture and makes the entrance water proof.

• The female, on an average lay 58-95 eggs in 14-54 days.

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Life cycle continue• The egg hatch in 1-9 days and the maggots bore into the pulp forming galleries.

• The attacked fruits decay because of secondary bacterial infection.

• The larva are full grown in 3 days during summer & 3 weeks during winter.

• The mature larvae come out of the rotten fruits and move away in jumps of 12-20 cm.

• These are made possible by folding & unfolding the two ends of the elongated body.

• After reaching a suitable place, they bury themselves about 5 mm deep in the soil and pupate.

• The pupae are barrel shaped, light brown & they transform themselves into winged adults in 6-9 days in the rainy season and 3-4 weeks in the winter.

• There are several generations in a year.

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• The maggot pollute and destroy fruits by feeding on the pulp.

• The damage caused by this fruit fly is most serious in cucurbits

• After the first shower of the monsoon, the infestation often reaches up to 100 percent

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Management: • The regular removal & destruction of the infested fruits • Frequent raking of the soil under the vine/ ploughing the infested field after crop

harvested can help in killing the pupae.• Install Cue lure trap (3 traps per ropani)• Foliar spray of malathion 50%EC @ 2ml/liter @2g jaggery/liter of malation solution.• Treat root zone soil of plants with Malation 5% Dust@ 20 kg/ha to kill hibernating

pupa• Use protein bait spray (Malathion+hydrolysed protein+ water at few spots in a field.

Both male and female are attracted to ammonia generated by protein sources.• Use food lure@ 1kg pumpkin and & 100 gm of jaggery and 10 ml malathion.• Apply bait spray containing 50ml malation 50EC +0.5kg of sugar in 50 liters of water

per ha. Repeat the spray if problem is serious.

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Spotted Beetle, Epilachna vigintioctopunctata / E. dodecastigma (Coleoptera: Coccinellidae)

• 2 species of spotted beetle Epilachna dodecastigma, E. vigintioctopunctata attacked different cucurbits and also solanaceous crops like brinjal, tomtato and potato.

• Another species E. demurili, attacks cucurbitaceous vegetable exclusively.

• Damage is caused by the beetles as well as the grubs.

• Beetles of all the three species are about 8-9 mm in length & 5-6 mm in width.

• E. viginitioctopunctata beetles are deep red and usually have 7-14 black spot on the each elytron whose tip is somewhat pointed.

• Beetles of E. dodecastigma are deep copper- coloured and have six black spot on each elytron whose tip is rounded.

• E. demurili beetles have a dull appearances and are light copper coloured. Each of their elytron bears six black spots surrounded by yellowish rings.

• Grubs of all the three species are about 6 mm long, yellowish in colour and have six rows of long branched spines.

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Life cycle• The life cycle & mode of damage of the three species of spotted beetle are very similar.

• Considering their abundance, E. vigintioctopunctata is the most important.

• It passes the winter as a hibernating adult among heaps of dry plants or in cracks & cervices in the soil.

• It resumes activity during March- April & lays yellow cigar shaped eggs, mostly on the underside of leaves, in batches of 5-40 each.

• A single female can lay up to 400 eggs in her lifetime.

• The egg hatch in 2.9-5 days at 35-25 °C.

• The grubs feed on the lower epidermis of leaves and are full grown in 7-17 days at 35-25 °C

• The pupae are darker and are found fixed on the leaves, stems and most commonly, at the base of plants.

• The pupal stage lasts from 5- 13 days at 35-25 °C.

• The pest passes through several breeds from March to October and its population maximum at the end of April or in early May.

• During the hot and dry months, the number declines greatly but the population again builds up in August.

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• Both the adults and grub cause damage by feeding on the lower and upper surface of leaves.

• They eat up regular areas of the leaf tissue, leaving parallel band of uneaten tissue in between.

• The leaves become a lace like appearances.

• They turn brown, dry up and fall off and completely skeletonize the plants.

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• Field sanitation

• Collect and destroy the infested leaves along with insect in initial stages

• Spray 625ml of malathion 50EC in 325 litres of water per ha at 10 days intervals as soon as the pest appears.

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Thank you