Now’s the time to be on the lookout for the potato leafhopper, a pest that can cause a significant
economic impact to alfalfa growers by reducing yields and quality.
Most growers have already had their first cutting, so now is the time for scouting for this pest because we know it has arrived in Ohio. Growers can begin scouting for the leafhopper once alfalfa regrowth reaches sufficient height for sweep-net sampling.”
In glandular-haired, leafhopper-resistant alfalfa, the economic threshold is three times the normal threshold, or three leafhoppers per inch of growth. In that case, the threshold would be 18 leafhoppers for 6-inch tall alfalfa, Hammond said.
“However, if the resistant alfalfa is a new planting this spring, growers might want to use thresholds meant for regular alfalfa during the very first growth from seeding,” he said. “After the first cutting, growers can then use three times the normal level threshold.
“Growers who take the time to sample and spray are better able to control the pests, while those growers who don’t tend to get hit by them.”
More information on potato leafhopper, including how alfalfa growing conditions might affect the threshold, can be downloaded at http://ohioline.osu.edu/ent-fact/pdf/0033.pdf