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Measuring corn rootworm pressure to make decisions for ‘22

Many growers across the Corn Belt are seeing increased corn rootworm pressure this year.

Adam Theis is the Pioneer corn marketing lead at Corteva Agriscience

“We are seeing a year across the Corn Belt where there is elevated corn rootworm pressure in many geographies and that goes back to what we saw in 2020 which for many geographies was also a higher (corn rootworm) pressure year followed by a mild winter and dry spring that allowed corn rootworm to overwinter and survive for the 2021 growing season,” he says.

He tells Brownfield there are a few ways to determine corn rootworm pressure.  

“You can dig roots and we recommend digging 10-20 plants per field and scoring for root injuries so you can really understand the pressure we’re seeing below that soil line. The other option we recommend is having sticky traps out there and what that allows you to do is catch those adults in sticky traps throughout the field. If we’re seeing populations that are les than 20 beetles per plant, we call that low pressure. If it’s higher than 50 beetles per plant, we consider that high pressure and we really want to talk about what the options look like next year with that farmer.”

A recent poll of 900 corn growers by Pioneer found that most farmers prefer to partner traits with best management practices and scouting.

“Over half of the 900 respondents said they’re using multiple modes of action to manage corn rootworm on their farm,” he says. “That may include going to soybeans and breaking that crop rotation cycle but it can also mean using insecticides and more.”

It’s likely that corn rootworm pressure will continue into the 2022 season. Theis says growers should reach out to their local Pioneer field agronomist to help make decisions for the next season.