INSECT PESTS OF CUCURBITS

R. RegmiAssistant professor

Department of entomology

Insect pests of cucurbits

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

Chrysomelidae)

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

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

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

Red pumpkin beetle Cucurbit stink bug

Spotted beetle, Epilachna beetle Cucurbit fruit fly

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)

Cutworm ` Flea beetle

White fly Peach aphid Banded blister beetle

Stem boring beetle

MYZUS PERSICAE (PEACH-POTATO APHID)

APHID COLONYALATE FORM APTEROUS

Soybean hairy catterpillar

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.

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.

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.

Management:

• 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

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.

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.

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.

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.

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.

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.

Damage:

• 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

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.

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.

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.

Damage:

• 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.

Management

• 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.

Thank you