Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Thrips, Aphids, White grubs and White files

1. Thrips

Important species:

• Chilly thrips, Scirtothrips dorsalis
• Ground nut thrips, Caliothrips indicus
• Blossom thrips, Frankliniella schultzei

Family: Thripidae

Order: Thysanoptera

Host plants: Polyphagous

Damage:

• Nymphs and adults lacerate the host tissue and imbibe on the oozing sap.
• Tender leaves and growing shoots are preferred
• Sometime buds and flowers are also attacked
• Infested leaves start curling and crumbling
• Buds become brittle and drop down
• Incidence is more in dry weather
• Transmit leaf curl disease.
• 30-50 per cent crop may be destroyed.
• In mixed cropping of onion and chillies, both crops suffer badly.

Identification:

• Eggs are minute and dirty white
• Nymphs and adults are small, slender, fragile and yellowish-straw in colour.
• Fringed wings which are uniformly gray in colour.

Life cycle:

• Reproduction is both sexual and parthenogenetic
• Eggs are laid on just under the leaf tissues
• Oviposition period is about one month
• Each female lays about 100 egg
• Total life cycle is completed in 14-18 days
• Many overlapping generations in a year.

Management:

• Spary the crop with dimethoate @ 0.03% or methyl demeton @ 0.025% or phosphamidon @ 0.04%
• Predatory thrips like Scolothirps indicus and Frankliothrips megalops have been found feeding upon Scirtothrips dorsalis in the nature.

2. Aphids

Cotton aphid (Aphis gossypii)

Green peach aphid (Myzus persicae)

Details have been discussed under brinjal pests

3. White grubs

Discussed under potato

4. White files

Discussed under tomato