Corn Insect Management

Farmers Must Focus On Three Areas To Manage Corn Insects

BETTY VALLE GEGG-NAEGER
MidAmerica Farmer Grower

MINER, MO.
   A general overview of corn insect management was presented recently by Dr. Scott Stewart, extension entomologist with the University of Tennessee.
   Stewart focused on three things, including insecticide seed treatments, when they are enough and when they might need a little help; managing corn borers in non Bt corn; and keeping up with the rapidly evolving Bt corn technologies.
   “Non Bt corn requires good management,” he said. “For example, pheromone traps for southwestern corn borer are a critical tool. We’ve actually just changed our threshold suggestions for southwestern corn borer in non Bt corn. We reduced our treatment thresholds and also included thresholds based on moth catches in pheromone traps. We will be timing at least some insecticide applications based on moth catches. Scouting corn borers in tasseling corn is a hot and time consuming job, and the moth traps may actually be better than the average scout at predicting infestations. The reality is, few people are scouting their corn for corn borers.”








  Dr. Scott Stewart, extension entomologist with the
  University of Tennessee, discussed insecticide seed
  treatments, managing corn borers in non Bt corn and
  keeping up with Bt technologies.

  Photo by John LaRose, Jr.









   The Bt technologies are the primary way farmers are managing corn borers. They have a lot of value, but there’s a lot of confusion about all the different options. With old and new Bt corn technologies out there at the same time, it requires some study to really understand what you are planting, what they control, and what the refuge requirements are.
   “I think the real take home with these new Bt technologies is not to expect yield increases,” Stewart continued. “The biggest value of the newer technologies is they simplify or reduce non-Bt refuge requirements, helping growers stay compliant with these requirements. Because the newer corns often have multiple Bt traits, we also expect that some pests will have a harder time developing resistance.”
   Of the seed treatments, he said there are circumstances where farmers might need to consider supplementing them, either by using higher rates or with an in-furrow, granular or liquid insecticide.
   “Be proactive in high risk fields or fields where you have a history of chronic insect problems,” he cautioned. “For example, consider using higher seed treatment rates or an in-furrow insecticide if putting a new field into production.
   “We often see big soil insect problems in pastures or CRP fields that are put into corn.” Stewart said. ∆
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower
MidAmerica Farm Publications, Inc
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