Studies on the Field Biology of Graminella nigrifrons,1 a Vector of Corn Stunt Virus in Mississippi2

Abstract

There are at least 3 generations of the black-faced leafhopper, Graminella nigrifrons (Forbes), in Mississippi. These generations, represented by peaks of adult activity, may be referred to as the spring, summer, and fall generations. High populations of this vector of corn stunt virus in April in the northern portion of the State occur about the time of spring corn planting. Although leafhopper infectivity is low (less than 1% of the natural population) the large first generation is most destructive to young corn. The second generation of leafhoppers is of lesser concern because the crop is older when exposed. G. nigrifrons survives through the winter as both adults and eggs on winter grasses, grain, and grazing crops. Adult leafhoppers actively lay fertile eggs in warm periods during the winter; thus there is no apparent diapause.