Source: University of Arkansas
Common Names: Tomato Fruitworm, Cotton Bollworm, Corn Earworm
Latin Name: Helicoverpa zea
Main Host(s): Corn, cotton, leafy and fruiting vegetables, ornamentals, tobacco, alfalfa.
In corn, the pest is known as the Corn Earworm, and in cotton it is called the Cotton Bollworm. On some crops H. zea occurs together with Heliothis virescens, together they are known as the heliothines. But H. zea is not limited to just these few host plants, as it infests many crops in the U.S. It has been found on many leafy and fruiting vegetables as well as ornamentals and field crops such as alfalfa, vetch, sorghum and tobacco.
Tomato Fruitworm adults are strong flyers and disperse northward in the summer where they can have 1-2 generations. Up to seven generations are possible in the Southern States.
A single female will lay on average 35 eggs per day and has a life span of 5-15 days. Eggs are laid singly, are pearly white or cream color, and measure about 0.6 mm in diameter. They are easily visible when first laid and can be found anywhere on the plant from the leaf stems to the calyx of the tomato, usually on terminal growth. Tomato Fruitworm larvae show burrowing behavior and after a short while on the foliage after egg hatch they will go into flower buds or fruiting structures. The 6-7 larval stages cover a 3-4 week period.
Tomato Fruitworm can do considerable damage to high value crops such as tomato, bell pepper, eggplant, snap beans, sweet corn and others. Since larvae bore into the harvestable crop, the tolerance for damage is low.
Pheromone traps are available for early warning of emerging and migrating moths. Scouting is absolutely necessary to assess the egg laying peak of the incoming population. In order to preserve beneficial insect populations, biorational control methods such as DiPel® and XenTari®, are often recommended early in the season. In addition, Tomato Fruitworm has developed resistance to many insecticides (most recently pyrethroids), so rotating DiPel and XenTari with conventional chemical insecticides provides a cornerstone to effective insect resistance management programs.