Don’t jump the gun when it comes to potato leafhopper control, says Eileen Cullen, University of Wisconsin extension entomologist. Make sure your fields have regrowth and leafhoppers are at economic threshold levels before spraying for the pest, she says.
“We have heard of people cutting and baling and then treating before there’s any regrowth. That would be called ‘cut, bale, spray’ and we’re trying to reinforce the integrated pest management (IPM) practice of ‘cut, bale and scout’,” says Cullen. Some growers may think pyrethroid insecticides have a long residual and, if sprayed right after baling or chopping, they’ll protect, she adds. “That’s not an IPM practice that we recommend. Just make sure you have some regrowth and actual leafhopper numbers before you make any spray decisions. We think the current thresholds can really guide people.”
This year’s increased demand and high prices for hay make it all the more important for growers to scout and keep on top of potato leafhopper thresholds. Spraying too late, or missing economic threshold populations, can be avoided by sweeping leafhoppers diligently, says Cullen.
For a one-page extension fact sheet on scouting for leafhoppers and leafhopper thresholds, visit www.uwex.edu/ces/crops/uwforage/alfalfa.htm. The PDF can be found under Pest Management, then Insects, as Cut-Bale-Scout.