Michigan alfalfa fields stunted by drought may also be infested with potato leafhoppers, a Michigan State University Extension educator warns.

Hot, dry weather favors potato leafhoppers, says Fred Springborn. The plant sap of drought-stressed plants is often more concentrated and nutritious for the insect, and biological control is below normal because the fungal pathogen isn’t active under low humidity.

“All of this results in potentially large potato leafhopper populations in fields,” says Springborn. “At the same time, stressed plants are less able to compensate for sap removal and the effect of the toxin, so the impact of potato leafhopper feeding is magnified.”

He urges growers to check fields using sweep nest and apply insecticide if leafhopper numbers are at or above economic thresholds.

“Controlling potato leafhoppers will help alfalfa make the most of the limited moisture that is available and maximize alfalfa yield and quality in the face of a short hay supply.”

For more information from Springborn, including recommended leafhopper thresholds, click here.