Thorax - 10-11 segments. Spiracles on segments 1 to 8. Prolegs on segments 3-6 and 10.
Habits - Herbivorous. Curls up when disturbed.
Pupa - In soil, in silken cocoon.
Moth flies by night and lays eggs on plants. Caterpillars remain close to where eggs were laid. Small caterpillars eats soft plant tissue, larger one burrow into the plant leaving a hole about 3mm wide. Pupa lives in soil beneath the plant. In Victoria there are 3 generations in a year.
Origin and History:
Cosmopolitan. Caterpillar is a pest of a wide variety of crops and plants including mallows. Eats buds, flowers, fruits and young leaves usually making a characteristic round hole. Caterpillars are often seen with their heads buried in this hole. They are major pests of maize, cotton, peas, sunflower, lupins, linseed, tomatoes, beans, lucerne and tobacco.
Some may migrate over considerable distances (It is thought that conditions in 1973 allowed migration from the north of WA to NSW). This may carry insecticide tolerant strains into susceptible populations or dilute tolerant populations with susceptible strains.
Orius flower bugs eat their eggs.
Management and Control:
A number of strains have become tolerant of common insecticides which can make control very difficult.