Found throughout Florida, but more commonly in the north, this multicrop pest attacks only ears on corn. Single eggs are deposited by moths on ears, and larvae feed extensively on silk, kernels and cob. Larval color varies considerably from green to dark yellow, pink, and brown accented with white and black stripes. Development is completed in the soil as a pupa with the whole process taking 28 to 40 days. Naturally occurring predators and parasitoids reduce fall armyworm and corn earworm populations in corn, but insecticides are important to produce the high-quality sweet corn we have come to expect.

Photo by Gregg Nuessly

Four Florida species in the genera Euxesta and Chaetopsis make up this complex of picture-winged flies. Silk feeding by fly larvae (maggots) reduce kernel number, but maggots also attack the kernels and cob. Eggs are placed mostly in the silk at the end of the ear in groups of five to 60. After feeding for 15 to 21 days, maggots leave the ear to pupate within the soil.  Flies emerge a week later and deposit eggs every two to three days for one to two months. Eggs and larvae are largely protected within ears, so adults are targeted for control, but two Euxesta species have become resistant to many insecticides.

Photo by Gregg Nuessly

Fall armyworm is the most important corn pest in Florida, because it feeds on all above-ground parts of corn plants. It overwinters in Florida and migrates north throughout the eastern seaboard states during the summer and early fall. Larvae feed on many additional grass and vegetable crops. The mostly brown- to black-colored caterpillars (larvae) emerge from masses of 75 to 200 eggs on leaves to feed for about three weeks before burrowing into the soil to complete development in the pupal stage. Adults (moths) emerge to start the process anew about seven to 10 days later.

Photo by Phil Sloderbeck

The small (1/2 to 5/8 inch), narrow-winged, reddish-brown to grey moths fly only 10 to 20 feet when disturbed during the day. Single or small groups of orange eggs are deposited on the soil or on leaf trash near food plants.  The hyperactive larvae are creamy white to turquoise blue with purple to brown rings. They feed on the stem and large roots of corn and other grass and legume crops from silk-lined tunnels they excavate around the plants. Damaged corn seedlings usually die or produce suckers that do not produce ears. Planting into fields free of weeds and previous grass crops is important for limiting infestation.

Photo by Gregg Nuessly

Wireworms are the larval stage of click beetles. They are hapless insects that come to lights at night, and which snap their bodies to fight off attackers or right themselves when found on their backs. Many species feed on corn in Florida, but the most damaging is Melanotus communis. Wireworm larvae live for nearly two years in the soil feeding on seeds, roots, and seedlings, before pupating in the soil. Adults emerge in the late spring and summer to deposit eggs in the soil. Wireworms reduce corn yield by killing seeds and seedlings if uncontrolled by at-plant soil or seed insecticide treatments.

Photo by Lyle Buss