Integrated pest management for the potato leafhopper ( Empoasca fabae) in alfalfa

Alfalfa, Medicago sativa L., is one of the best quality dairy forages and as the principal forage legume in the U.S., is grown on roughly 10 million ha. Potato leafhopper, Empoasca fabae Harris, is its most economically damaging insect in the Midwest and northeast United States. Integrated pest management (IPM) programs for E. fabae in alfalfa consist of sampling and monitoring throughout the season, foliar insecticide treatments when economic thresholds are reached, host plant resistance and the cultural control of early harvest when economic thresholds are reached within a week of a planned harvest. The work presented here gives a thorough review of E. fabae ecology and biology, migration patterns and injury to host plants. A thorough review of available pest management strategies for E. fabae in alfalfa is discussed (chapter 1). An IPM system incorporating host plant resistance and orchardgrass intercroppings as a cultural control is studied with regards to affects on E. fabae abundance and alfalfa yield and forage quality (chapter 2). Alfalfa yield loss response to E. fabae feeding is assessed in order to validate the current economic injury level and economic threshold models for both susceptible and resistant alfalfa varieties (chapter 3). Lastly, soil fertility treatments are considered as a potential cultural control tactic for managing E. fabae in response to farmer observations (chapter 4).