Aphid Control Spotlighted During Small Grains Update

The annual Small Grains Update provides an opportunity for growers to learn about research projects, market outlooks, legislative previews and receive updates from local county organizations. Angie Peltier, University of Minnesota Extension crops educator, is a regular on the circuit, which makes stops in counties throughout northwest Minnesota. She used most of her time to talk about how producers can best manage something else that’s a regular occurrence throughout the region: soybean aphids.

Soybean aphids, which winter on buckthorn and spread to soybean fields in the summer, are soft-bodied insects that feed on the plant sap, reducing soybean yield and quality. According to Peltier, the summer of 2024 was an ideal year for the spread of soybean aphids throughout parts of Minnesota, which underlines the importance of constant scouting.  

“When you have a lot of mild temperatures, mid 70s and 80s and not a lot of natural enemies that can help keep your aphids in check, your aphid populations can double in just 3-4 days,” Peltier said. “That’s why we really recommend scouting and not relying on your neighbor.” 

Peltier drove home the importance of sticking to the economic threshold, which is 250 aphids per plant, when determining when to spray for aphids. While it may seem like a high number, she notes that the threshold is set low enough so that producers have time to make an application before reaching the economic injury level.  

“If you spray before that 250 aphids per plant threshold, you might be spraying unnecessarily or you may have to spray twice, so a well-timed application based on scouting is key,” Peltier said. “Using the economic threshold also takes the emotion out of the decision.”  

Peltier, whose projects are sponsored in part by the soybean checkoff, also encouraged growers to rotate their chemistry when spraying for aphids, as resistance to pyrethroids continues to be an issue.  

“The goal is to hit the population with something different, and by changing it up it’ll help slow the speed at which our populations develop resistance tactics,” Peltier said.