Source: DuPont Pioneer
While it’s still unclear how much corn rootworm (CRW) pressure will be experienced this year, it’s important to plan ahead to manage the yield-robbing pest. DuPont Pioneer entomologists have developed best management practices (BMP), which also stands for break, manage and protect. Clint Pilcher, DuPont Pioneer director of scientific affairs, insect resistance management, offers up some advice from that management program to control for CRW this year.
“To effectively manage corn rootworm, growers need a long-term plan to help reduce the risk of overwhelming populations,” said Pilcher. “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 hybrid that includes a Bt-trait. In high pressure CRW zones, Pioneer 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.”
Layering multiple CRW control options can be particularly effective. 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.
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.”
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