The most important economic advantage offered by leafhopper resistant alfalfa is yield protection in the presence of leafhopper pressure. While yield reducing leafhopper infestations do not occur each year, the probability of experiencing heavy infestations at some time during the life of a stand is high. Other benefits exist for this new technology in addition to the yield advantage. While an occasional insecticide application may still be necessary under extreme leafhopper pressure, the use of insecticide for control of PLH in alfalfa will be greatly reduced for growers using resistant varieties. New economic thresholds for insecticide treatments will be needed for leafhopper resistant varieties.
Resistant varieties have the indirect benefits of maintaining plant health and stand persistence.
Wounds from insect feeding not only weaken the plant but also predispose it to diseases and premature stand thinning. It is unlikely that potato leafhopper will be dramatically affected by the widespread use of resistant alfalfa varieties. Leafhoppers are adapted to a wide variety of hosts and move between them readily. Some evidence suggests that glandular hair alfalfa does not significantly displace insect pests or natural enemies. Therefore the insect community in leafhopper resistant alfalfa will not greatly differ from those of susceptible varieties.