Simply put - very significant and extremely costly damage. Literally millions of dollars are stolen from alfalfa growers each year by leafhoppers in terms of lost yield and quality. Established Stands Studies have shown the average loss from an existing stand of alfalfa is 500 pounds per acre per harvest where infestation exists. The loss from new seedings is even more substantial than that from established stands. The loss is not limited to just annual yield reduction.
Recovery is improved - plants are more vigorous and regrow faster after each cutting.
Stand life is improved - plants which are not damaged are more healthy and better able to survive the winter. Yield the following season is improved - plots have shown alfalfa stands produce 0.5 ton more hay the following season if leafhoppers were controlled the previous year. Recent research has shown that leafhoppers also overwinter on pine trees in Georgia and Tennessee, and migrate from there to the northeast each spring. Because the leafhopper removes juices from the alfalfa plant and blocks vascular tissue as it feeds, it causes a wedge-shaped yellow area to occur in the leaf tip. As damage increases, the entire leaf turns yellow, giving a yellow or burned tint to all the plants in the field.