Early Scouting Can Help Manage Corn Pests

Late planting, wet soils may lead to more corn pests

DES MOINES, Iowa.– Growers can minimize the risk of lower corn yields now by scouting for pests, say experts from Pioneer Hi-Bred, a DuPont business.

Because of wet conditions in many areas of the Corn Belt this spring, late planting may become an issue. Insects tend to thrive in wet, cool soil conditions, so monitoring fields for insects as soon as the crop emerges is very important, says Paula Davis, Pioneer senior manager for insect and disease traits.

“Early insect scouting should be a major consideration in managing corn pests,” Davis says. “Once the seed comes up, monitor for any signs of insect damage.”

Insects such as white grubs, black cutworms, wireworms and armyworms are ones to watch for early in the growing season.

“From April to May, significant captures of black cutworm moths have been reported in several states including Missouri, Indiana and Kentucky,” Davis says. “Growers throughout this region should watch for signs of leaf feeding and cutting.”

Young black cutworm larvae feed on weeds such as mustards and other biennials. Ideally, removing weeds 10 to 14 days or more ahead of planting will reduce the survival and risk of additional egg-laying.

Two pests, wireworms and grubs, would have been a bigger issue if corn was already planted and the temperature turned cold, according to Davis. “There haven’t been many reports of these two insects yet because of delayed planting in many areas. These insects are more active in cooler, moister soil conditions, and once it gets warmer they go further down into the soil, lessening their impact.” Growers should watch for signs of damage once corn begins emerging. For wireworm and white grub damage, look for stand reduction. White grubs feed on roots of seedlings, which will cause irregular stands since pruning takes place on the roots.

Armyworm moth flights have been reported in Missouri, Indiana and Illinois. “Armyworms are attracted to grassy areas, such as pastures and cereal crop fields,” Davis says. “We tend to see more of these in southern areas, like Missouri, southern Illinois, Kentucky, Tennessee and southern Indiana. Growers in these areas should watch for armyworms as they tend to migrate from grassy areas to cornfields.”

Even though western bean cutworm pests usually aren’t active until late June into July, it is never too early to prepare. Western bean cutworm is moving eastward, and recently expanded into Indiana, Michigan, Ohio and Ontario, but the western areas of the Corn Belt also should continue to monitor the pest.

With all of the insect challenges growers face, there are solutions. One is choosing a hybrid with the appropriate traits. The Herculex® line of technologies protects growers against a number of corn pests. Corn hybrids with Herculex® I and Herculex® XTRA technologies have very good protection against black cutworm, as well as western bean cutworm.

There also are insecticide seed treatments available, as well as insecticide applications. For instance, DuPont™ Asana® XL insecticide provides longer-lasting control of cutworms, armyworms and other corn pests, and it can be used as a preventive treatment before or at planting in fields that have a higher risk of cutworm infestation. It is also an excellent choice for postemergence applications in conjunction with a scouting program.

Tillage practices are part of the equation for pest management, and no-till operations tend to have a higher likelihood of pest challenges. Weed management and scouting also should be considered because of insects that are attracted to weeds.

“We want to provide solutions for growers so they can reach the greatest yield potential,” Davis says. “It is important to scout for pests throughout the growing season, especially early, because insects are small and easier to maintain and manage with insecticides.”

If a grower has indicators of an insect issue, he or she can contact a local Pioneer agronomist to identify the issue and recommend specific follow up.

Pioneer Hi-Bred, a DuPont business, is the world’s leading source of customized solutions for farmers, livestock producers and grain and oilseed processors. With headquarters in Des Moines, Iowa, Pioneer provides access to advanced plant genetics in nearly 70 countries.