ANALYSIS - Although the extent of corn rootworm (CRW) pressure in 2014 is yet to be determined, entomologists say planning this season for future rootworm populations is the best way to control the yield-robbing pest.
Earlier this year five Illinois counties reported confirmed cases of field-evolved resistance to Bt corn (Cry3Bb1 protein) by western corn rootworm, and a University of Illinois entomologist said now is the time to move forward aggressively with integrated pest management (IPM) strategies.
In August 2012, in cooperation with an Iowa State University lab, Mike Gray said he confirmed resistance in Henry and Whiteside counties in northwestern Illinois.
Working with Joe Spencer of the Illinois Natural History Survey and utilizing single-plant bioassays with larvae collected last summer, Gray said resistance to the Cry3Bb1 protein had also been confirmed in McDonough, Mercer, and Sangamon counties earlier this year.
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.
Growers are advised to scout their fields in order to protect their crop from developing issues.
Denny Cobb, agronomist at Beck’s Hybrids told AgriNews: “One thing I encourage a lot of farmers and growers to do this time of year, especially at the halfway point, is to get in the fields and do root digs — evaluate how well the roots are developing.
“Farmers also need to get a nutrient scorecard by taking leaf tissue analysis for corn and beans and seeing if their crops need any micronutrient application now," said Mr Cobb.
“To effectively manage corn rootworm, growers need a long-term plan to help reduce the risk of overwhelming populations,” added 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.”