Empoasca (Homoptera: Cicadellidae) abundance and species composition in habitats proximate to alfalfa

To determine the role of habitats close to alfalfa on the population ecology of potato leafhopper, Empoasca fabae (Harris), eight such habitats (e.g., deciduous trees, weedy areas, and forest understory) in east-central Illinois were sampled weekly from May through October, 1982-1984, for potato leafhopper and morphologically similar, congeneric species. Of all Empoasca males collected during 1983 and 1984 outside of alfalfa fields, E. fabae were most abundant (82.8%), followed by E. solana DeLong (7.3%), E. recurvata DeLong (6.8%), E. erigeron DeLong (2.7%), and E. bifurcata DeLong (0.4%). Three-fourths of the E. recurvata males were collected mid-September or later, and all of the E. solana males were collected in the apple orchard habitat. Although alfalfa and some deciduous trees (e.g., oaks and maples) typically were colonized first by adults in May, the first generation of nymphs was able to complete development only outside the alfalfa because the first harvest occurred soon after migratory adults arrived. Abundance in any one habitat was variable during the summer, often fluctuating between high numbers during one week and zero the next. After alfalfa was cut, adults were often abundant in habitats immediately adjacent to the field. These results indicate that potato leafhopper commonly occurs in such habitats, and that these habitats may serve as a population source or sink for adults dispersing to and from alfalfa