Corn Earworm

Helicoverpa armigera

(formerly Heliothis armigera or Heliothis sorghicola)

Also known as Cotton Bollworm

Family: Noctuidae

Order: Lepidoptera

Description:

Adult

Night flying moths with eyes that reflect orange light. Attracted to lights.

Colour - Front wings are variable in colour but often grey-yellow with purplish tints. Rear wings more consistent being silvery grey with dark brown tips.

Body - Medium size. Stout. Long hair scales.

Wings - 2 Pairs. Membranous. Hairy. Wing-span 20-30 mm

Mouthparts -

Antennae - 3 segments.

Legs - Broad overlapping scales. Feet (Tarsi) have 5 segments.

Head - Broad overlapping scales. Large rounded compound eyes.

Thorax - Broad overlapping scales. 3 segments. Front segment much smaller. Hairy

Abdomen - Broad overlapping scales. 7-11 segments. Spiracles on segments 1-7. Hairy

Egg -

Habits - Can't fly when cold. Often lie flat on stems or bark.

Caterpillar -

Colour - Brown, green or pinkish with a broad pale bands down each side and dark flecking. Markings depend on the plant that it is feeding on.

Body - Fleshy. Cylindrical. Slightly hairy. Spiny skinned 20-40 mm long, 3-10 mm wide.

Mouthparts - Chewing.

Antennae - Short. 3 segments.

Legs - 5 segments. Single claw on end.

Head - Hard.

Thorax - 10-11 segments. Spiracles on segments 1 to 8. Prolegs on segments 3-6 and 10.

Abdomen -

Habits - Herbivorous. Curls up when disturbed.

Pupa - In soil, in silken cocoon.

Biology:

Life Cycle:

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 3 mm wide. Pupa lives in soil beneath the plant. In Victoria there are 3 generations in a year.

Habitats:

Origin and History:

Distribution:

Significance:

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.

Related Species:

Armyworm, Bogong moth, Cluster caterpillar, Common Armyworm, Corn Earworm, Cutworms, Helicoverpa or Heliothis, Inland Armyworm, Loopers, Native budworm, Southern Armyworm.

Similar Species:

References:

CSIRO. The Insects of Australia. Melbourne University Press. (1991) p38f2.9, 107, 108, 914.

Froggatt, W.W. Australian Insects. William Brooks & Co. p265.

Jones, D. & Elliot, R. Pests Diseases and Ailments of Australian Plants. Lothian Publishing Co. p116-117.

Victorian Department of Agriculture. Insect Bulletin p25-27.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.