Time to Start Scouting for Potato Leafhoppers in Alfalfa

Jun 14, 2022

By Kelley Tilmon and Mark Sulc et.al

We are receiving reports of near or at-threshold levels of potato leafhopper in alfalfa. As second-cut alfalfa grows, farmers should scout for resurging numbers in their fields. Younger alfalfa is more susceptible to damage at lower leafhopper numbers. If alfalfa is more than 7 days from a cut and plants are under normal stress, a good rule of thumb for a treatment threshold is: when the number of leafhoppers in a 10-sweep set is equal to or greater than the height of the alfalfa. For example, if the alfalfa is 8 inches tall and the average number of leafhoppers per sample is 8 or higher, treatment is warranted. If the average is 7 or lower, the grower should come back within a few days to see if the population is higher or lower. Vigorous alfalfa can tolerate higher numbers, and stressed alfalfa can tolerate fewer. Special attention should also be paid to alfalfa fields that were damaged by fall armyworms last year.

Source : osu.edu

Video: Wisconsin Corn and Soybean Weed Management Updates and Considerations for 2026 and Beyond

Dr. Rodrigo Werle, associate professor and extension weed scientist, UW–Madison, shares the latest updates and future considerations for corn and soybean weed management in Wisconsin. This presentation covers herbicide resistance trends in waterhemp, including newly confirmed cases of HPPD and S-metolachlor resistance, and emphasizes the importance of residual herbicides and strategic tank mixes for consistent control. Rodrigo also introduces upcoming technologies like Vyconic soybeans and new herbicide products, discusses integrated weed management strategies such as planting green with cover crops, and highlights practical recommendations for 2026 and beyond.

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