Potato leafhoppers inject saliva into plants as they feed, resulting in abnormal cell growth and interference with transport of fluids in the leaves. Prior to this a slight yellowing or curling of leaves occurs, which is often overlooked. Severely damaged plants are stunted and chlorotic. Leafhopper burn appears as yellow wedge-shaped areas on the tips of leaflets. Damage reduces forage yield and quality in several ways.
Damage also results in substantially lower protein levels.
General stand vigor is decreased, leading to slow regrowth following cutting and increased winter kill. Detection Check alfalfa, clover, and trefoil fields for leafhoppers on the latter part of June or shortly after the first cutting, whichever comes first. A heavy duty sweep net should be used to properly sample for potato leafhoppers. Take 20 sweeps in five representative areas of the field and determine the average height of the crop at each location. If the infested crop is almost ready to cut, remove it first, check the regrowth and spray if needed.