Effects of Alfalfa Cuttings on the Potato Leafhopper, Empoasca fabae1

Abstract

For the past 25 years, the recommended cultural control in Wisconsin for the potato leafhopper, Empoasca fabae (Harris), has been to delay the first cutting of alfalfa until well into the bloom stage. It was necessary to re-evaluate cutting practices in the light of recent information on the spring immigration of the insect. Several different alfalfa-cutting schedules were evaluated in southern Wisconsin over a 5-year period in relation to the effect on potato leafhopper populations. The most important population factor was the timing of the major influx of adult leafhoppers in the summer with a suitable or unsuitable host plant condition. The time of this influx was variable enough to negate any consistent advantage gained by a delayed first cutting. A second cutting at very early-bloom or late-bud stage would have eliminated the nymphal peak and greatly reduced the occurrence of yellowing in each plot cut on a three-cutting schedule, except for 1955.