Wireworms are an increasing problem in some Kentucky cornfields. Prevention is the key to controlling these insects that can destroy seeds and young plants.

“We are seeing more and more wireworm problems and we aren’t sure why that is happening,” said Ric Bessin, an entomologist with the University of Kentucky Cooperative Extension Service .

Bessin has been conducting trials using seed treatments to determine their effectiveness against wireworms and other soil-borne insects in HardinCounty , where some areas have tremendous wireworm problems. Five new seed treatments have been developed in the past couple years. This technology treats seeds prior to planting to deliver pesticides.

“Seed treatments have caught the eye of many producers,” Bessin said. “What we’ve seen so far is seed treatments that are holding up well and are doing as well as soil applied insecticides. The good news is many of the seed treatments are very economical.”

When considering commercial seed treatments, growers need to remember that not all treatments provide the same levels of protection. Different rates may also be available on seed, providing differing lengths of protection. If seed treatments will be used, they must be specified when placing seed corn orders later this year.

Wireworm control has to be preventative, he said. Once growers begin to see damage from wireworms, there is nothing they can do other than to decide whether the plant stand is poor enough to warrant replanting.

Wireworm damage results in an uneven stand and skips in the field where seeds and plants have been killed. Wireworms feed on the germinating seeds and on young seedlings.  

There are five to six common wireworms in the state and as many as 12 different species. Their lifecycles can be two to five years. That could mean the same worm could damage your corn field this year, your soybeans next year and your corn again the following year.

Bessin told farmers at a recent field day in HardinCounty that unless they have a problem with soil insects, they may not need to use seed treatments or other preventative tools.

“I’m a strong believer in finding the tools that are going to bring you benefit on your farm and there are a lot of tools out there,” he said. “All of them might not be bringing you a benefit, not because the tool doesn’t work but because you don’t need it.

“Tools have specific uses and it’s best to know what tools you are going to need and use those tools,” he said. “Sometimes the best choice is not to use any tools because you don’t have a problem.”

For growers with a wireworm problem, Bessin recommends not using the same controls year after year in order to reduce possible resistance.

Farmers have a number of alternatives to use for controlling soil insects in corn in addition to seed treatments. These include crop rotation, granular insecticides, liquid insecticides and biotech varieties available for some pests.

A producer needs to determine what will work best in his operation based on costs, the pests to be controlled, equipment and the degree of control expected. Rotation should always be considered as a means of reducing soil insect problems.

For more information on corn insects and controls contact the local Cooperative Extension office.

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