Planting a cool-season grass with non-potato leafhopper-resistant alfalfa will reduce leafhopper damage and increase yield compared to having no grass in the mix, according to a recent study conducted in New York and Pennsylvania. Adding a grass to potato leafhopper-resistant alfalfa offered limited benefits in addition to those already provided by the resistant alfalfa. The research, funded by Northeast Integrated Pest Management, looked at potato leafhopper-resistant alfalfa varieties spring-seeded with orchardgrass, tall fescue or timothy. During the seeding year, there were limited differences between grass species.