Some Factors Influencing Population Growth of the Aster Leafhopper in Anoka County, Minnesota1

Abstract

The effects of host plant relations and weather conditions on the abundance of the aster leafhopper, Macrosteles fascifrons (Stal), were studied under greenhouse and field conditions from 1958 to 1962. Host plants preferred for both feeding and reproduction included barley, Hordeum vulgare L.; crabgrass, Digitaria sanguinalis L. (Scop.); fowl-meadow grass, Poa palustris L.; horseweed, Erigeron canadensis L.; lettuce, Lactuca sativa L.; oats, Avena sativa L.; rye, Secale cereale L.; and wheat, Triticum aestivum L. Flax, Linum usitatissimum L., was sometimes a suitable host in the field but not in the greenhouse. Carrots, Daucus carota var. sativa L.; potatoes, Solanum tuberosum L.; dill, Anethum graveolens L.; and radishes, Raphanus sativus L., were important food plants but not good breeding hosts. Later plantings of oats, rye, and wheat had significantly higher populations of leafhoppers than early plantings. The seasonal sequence of host plants was important in determining the buildup of leafhoppers. Snow cover during the winter appeared to provide protection for overwintering eggs of the leafhopper. This species may disperse from north to south during the summer as well as from south to north in the spring. Local conditions which appear to be most favorable for a severe outbreak of the aster leafhopper are (1) a large influx of leafhoppers in the spring, (2) warm weather in May and June to permit rapid increase of the leafhoppers, and (3) adequate precipitation and soil moisture to provide an abundance of succulent host plants.