Although the extent of corn rootworm (CRW) pressure in 2014 is yet to be determined, DuPont Pioneer entomologists say planning this season for future rootworm populations is the best way to control the yield-robbing pest. The CRW best management practice (BMP) from Pioneer also stands for break, manage and protect. These integrated pest management BMPs help growers manage the damaging CRW pest while preserving the effectiveness of insect control biotechnology traits long into the future.
           
“To effectively manage corn rootworm, growers need a long-term plan to help reduce the risk of overwhelming populations,” said Clint Pilcher, DuPont Pioneer director of scientific affairs, insect resistance management. “CRW management goals should include reducing the population to maintain trait performance, as opposed to attempting to eradicate this insect.”

Pilcher, along with other Pioneer experts, suggests a set of BMP strategies based on breaking the life cycle of CRW, managing CRW beetle populations and protecting corn yield potential with a Pioneer brand hybrid that includes a Bt-trait. In high pressure CRW zones, Pioneer professionals may recommend an insect control option with multiple modes of action above and below ground.

“The BMP strategy allows the grower to have more options available for CRW control,” Pilcher said. “It’s really about keeping populations in check and not scrambling to use every available control option in one field at one time.”

Growers are encouraged to work with their trusted Pioneer sales professionals in building a plan to effectively use the management tools available to them and help avoid aiding the development of resistant insects caused by layering multiple CRW control options. For instance, if you plant a traited product one year in a continuous corn scenario and experience high beetle populations, then spraying the adult beetles makes sense. Next year, in that same field which sustained high beetle numbers the prior year, planting soybeans or another alternative crop is the best control option. Or if planting corn, either plant a different traited product or consider applying a soil insecticide on top of non-Bt corn.

“What growers should avoid is using all of their CRW control options all at once,” Pilcher said. “Growers should be aware of the CRW pressure in their fields and avoid using soil insecticides as a blanket treatment on top of all traited products.”

Knowledge is power for growers concerned about corn rootworm pressure in their fields. Consider the history of a field when evaluating CRW management options and planning a long-term control strategy:

  • Continuous corn fields are typically hot spots for CRW insect pressure.
  • Keep track of what CRW traits were used in each field and try to understand trait product use in the area (including your neighbors’ fields if possible).
  • If continuous corn is your primary cropping strategy, then plan to put at least 20 percent of your farm in a soybean or alternative crop rotation every year. Diversify your control strategy to reduce the impact of CRW populations.

“I encourage growers to scout their continuous corn fields when silking begins,” Pilcher said. “Select your higher-risk fields based on cropping history, trait use and planting times. Also, later planted fields tend to be more attractive to CRW adults.”

“With a history readily available about a field’s corn rootworm infestations, a more sustainable management plan can be implemented to control CRW populations,” Pilcher said.