Corn Stunt Virus: Transmission by Three Cicadellid Vectors1

Abstract

The duration of nymphal instars of Dalbulus maidis (DeLong & Wolcott), D. elimatus (Ball), and Graminella nigrifrons (Forbes) was 18.5, 20.2, and 23.5 days, respectively, at 24±2°C. The life span of adult D. maidis, D. elimatus , and G. nigrifrons was 56.5, 51.5, and 38.2 days, respectively. G. nigrifrons was inefficient in acquisition and transmission of corn stunt virus (CSV) to plants in comparison with both Dalbulus species. D. elimatus was able to acquire CSV during access feeding times of 15 minutes. G. nigrifrons and both species of Dalbulus transmitted virus during 4-hour and 15-minute inoculation access feeding periods, respectively, but not at shorter periods. The minimum incubation period of CSV in colonies of the 3 leafhoppers ranged from 22 to 26 days in G. nigrifrons , 17 to 22 days in D. maidis , and 14 to 15 days in D. elimatus at 24±2°C. The frequency of virus transmission by G. nigrifrons and D. elimatus showed that infective insects of both species transmitted virus to almost every plant they were transferred to at 1-, 2-, and 4-day intervals. Poor and efficient vectors were observed in both species. In spite of its comparative inefficiency in acquisition and transmission of CSV, G. nigrifrons might play an important role in the spread of the virus, since it is abundant throughout the corn-growing areas of North America, and it can survive on a variety of plant hosts.