Across the corn belt depending on time of year | From what I read, you have been on an annual rotation of corn and beans for 20+ years
You are located in the center of where rootworm adapted to this annual rotation by laying eggs in soybeans rather than in corn resulting in rootworm damage in 1st year corn.
A few years back, the Illinois entomologist mentioned that the “rotation resistant” strain of rootworm had also become resistant to traits with rootworm damage being observed in RW traited corn grown in the annual rotation cycle. It has also been mentioned that rootworm populations have been low in Illinois the last several years.
Without any information regarding the number of rootworm beetles “playing around” in your soybeans, you are flying blind rootworm risk wise.
So what are the risks? Non RW traited corn without insecticide could escape without significant damage if rootworm egg laying in soybeans was low or it could be a significant yield hit. No data = no way to evaluate risk. It is generally accepted that 1 nodes of roots destroyed by rootworm = 10-15% yield hit depending on a summer with sufficient rain or a dry summer.
Non rootworm traited corn using bifentrin in furrow at planting: Bifentrin is cheap, easy to apply as a liquid in furrow and highly variable in performance against rootworm. Significant control failures under moderate to high rootworm pressure especially during wet springs/early summers
Non rootworm traited corn using Aztec or Force: More effective rootworm control than bifentrin. Liquid formulations easier to apply with planters without insecticide boxes but less effacious than the grannular formulations. Probably similar costs to RW traited corn.
Here are the risks as I see it as a long-term corn entomologist. What is your level of risk taking?
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First time conventional corn questions
