Effect of environmental conditions and leafhopper gender on Maize chlorotic dwarf virus transmission by Graminella nigrifrons (Homoptera: Cicadellidae).

To determine the most economical and efficient means to maintain cultures of Maize chlorotic dwarf virus (MCDV) and to screen for host plant resistance to MCDV, we evaluated the effects of temperature, light intensity, daylength, atmospheric pressure, and leafhopper gender on the frequency of transmission of MCDV by Grarminella nigrifrons Forbes (Homoptera: Cicadellidae). Female leafhoppers transmitted at higher frequencies than males under most conditions. In temperature studies, transmission rates for both male and female leafhoppers progressively increased as temperatures rose from 20 to 30 degrees C. At high light intensities, both males and females transmitted at greater frequencies than they did at low. Similarly, longer day lengths were correlated with higher transmission rates for both sexes. No significant differences in transmission rates were observed in response to differences in atmospheric pressure. The results also showed that transmission rates under most conditions are high enough to overcome potential ambiguities caused by inoculated susceptible plants that do not become infected (disease escapes) when screening for resistance.