Crops: Cotton Insect Pests
Aphid -Aphis gossypii (Aphididae : Homoptera)
- Polyphagous in nature and widely distributed.
- Aphids are small soft bodied insects with a pair of tubular structures, cornicles, present on the 6th abdominal segment.
- Nymphs are light yellowish green, or greenish black or brownish
- Adults are mostly wingless, but few winged forms can also be seen with thin transparent wings.
- Females either lay eggs or directly produce young ones which mature in about a week, hence population build up is quite fast
- Nymphs and adults colonise on the undersurface of the young leaves or shoots and suck the sap resulting in crinkling and curling of the leaves.
- Leaves appear shiny and sticky due to honey dew excreted by the insects. Later, sooty mold grow on honey dew and leaves have a black coating.
- Cool weather and humid conditions favour multiplication, while heavy rains wash away the aphid colonies.
- When 15-20% aphid infected plants are observed, control measures may be taken up.
- In nature several species of coccinellids and syrphids prey on aphids
