(Source: Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org)

Vegetable growers know that as the summer growing season approaches, staying on top of field scouting is crucial. Having a plan in place before pests reach critical levels will help protect crops against yield-robbing damage all season long.

Because lepidopteran caterpillar pests can cause crop damage early in their lifecycle, it is important to proactively identify them.

Combatting lepidopteran insects can be difficult, and they’re often a top-of-mind pest season after season since they migrate from host to host throughout the year. If they’re not properly managed, these pests can result in significant yield loss. Growers are encouraged to use a foliar insecticide with larvae to help mitigate damage.

In tomato fields, the most common caterpillar insects are tomato fruitworms and armyworms. Tomato fruitworms lay eggs underneath plant leaves and petals, and once hatched, larvae move their way into the fruit. Feeding results in a watery internal cavity and may cause fruit to ripen prematurely or become susceptible to bacterial infection.

Similar in appearance, beet armyworms and southern armyworms can both cause defoliation and fruit loss through larvae feeding. Adults lay eggs on young plants, where larvae hatch and begin to feed near the egg cluster. Beet armyworm larvae grow up to 25 millimeters long, and have smooth, green bodies with mottled dark lines along the back. Southern armyworm larvae can grow up to 35 millimeters and are green or black-green with a uniform light brown or red-brown head.

Larvae are most active at night and can be found on the lower surface of crop leaves. As the larvae grow, they skeletonize the plant and feed on young fruit. After they pupate in the ground, mottled brown, gray and white moths emerge and mate, restarting the damaging cycle for the next season.

For fruiting vegetable crop protection, we recommend Besiege® insecticide, a broad-spectrum, foliar-applied insecticide providing both rapid knockdown and long-lasting residual control of lepidopteran, sucking and chewing insect pests. It controls worms at every life stage, from egg to adult, using vigorous active ingredients – chlorantraniliprole and lambda-cyhalothrin – and dual modes of action.

Don’t leave your crops and yield susceptible to damaging insect infestations. For more scouting and management insight into fruitworms and armyworms, contact your local retailer or Syngenta representative.

Sign up for the Know More, Grow More Digest to receive twice-monthly agronomic e-mail updates pertinent to your area.

All photos are either the property of Syngenta or are used with permission.

Performance assessments are based upon results or analysis of public information, field observations and/or internal Syngenta evaluations. Trials reflect treatment rates commonly recommended in the marketplace

Important:  Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status.

Besiege is a Restricted Use Pesticide. Besiege is highly toxic to bees exposed to direct treatment on blooming crops and weeds. Do not apply this product or allow it to drift onto blooming plants while bees are foraging adjacent to the treatment area.