Tomato Fruitworm

AVRDC
Crop Protection Guides

*Tomato Insect Pests* Tomato Fruitworm (Helicoverpa armigera Hübner)	In This Guide
	Damage symptoms
	Insect characteristics
	Where to look
	Technical information
	Control

Damage symptoms A small darkened partially healed hole at the base of the fruit pedicel is evident. The inside of the fruit has a watery cavity that contains frass and decay. Tomatoes ripen early but are not usually marketable.
		Larva feeding on top of tomato

Insect characteristics Chewing mouthparts. The young, small caterpillars have prominent rows of dark bumps (tubercles) on their backs. The older, larger ones vary in color from dark gray to light brown and have lengthwise stripes on their bodies. The adult form is a moth.
		Larva feeding inside the fruit

Where to look

Look at the base of the fruit stem. If you find a darkened hole, remove the fruit and cut it open. Inside you will notice tunneling caused by the insect. This cavity may contain frass and decay. Often the caterpillar is present.

Technical information In warm areas several generations occur. Caterpillars sometimes move from one fruit to the next destroying only small portions of each fruit. Pupation occurs in the soil near the base of the plant. Adults are extremely fecund; they are active during the day but more commonly at dusk. Eggs are laid on the tomato foliage. Young caterpillars feed on the leaves. Other hosts of this pest include chili pepper and maize.
		Healthy fruitworm egg

Control

Monitor the pest by selecting a leaf from 30 random tomato plants. Choose leaves located below the highest open flower. Healthy eggs are white with a reddish ring. If more than five healthy eggs appear, begin treatments. Pesticide treatments are also required when large numbers of small caterpillars are found feeding on leaves.

This pest has developed resistance to many insecticides. Select an effective chemical. The following insecticides are often used for control: esfenvalerate (Asana), methomyl (Lannate), Bacillus thuringiensis, azinphosmethyl (Guthion), carbaryl (Sevin), and Pyrethrin/Rotenone.

Parasitic wasps, especially Trichograma spp., are important natural enemies. Fruitworm eggs turn black when parasitized.

Avoid planting tomato near corn or cotton to prevent heavy pest infestations.

Last updated: July 2000.
Information from: Field Guide: Insect Pests of Selected Vegetables in Tropical and Subtropical Asia. 1995. B.L. Parker, N.S. Talekar and M. Skinner. Publication 94-427. Pest control recommendations added to internet version.

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