Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 22, 2004
Publication Date: June 1, 2004
Citation: Gingery, R.E., Anderson, R.J., Redinbaugh, M.G. 2004. Effect of environmental conditions and leafhopper gender on maize chlorotic dwarf virus transmission by graminella nigrifrons. Journal of Economic Entomology. 97(3):768-733. Interpretive Summary: Maize chlorotic dwarf virus (MCDV) causes an important stunting disease of corn in the United States. MCDV is transmitted from plant to plant by insects (leafhoppers), and MCDV inoculation of corn lines using leafhoppers is often used to screen for resistance. During such testing, it is important that the efficiency of leafhopper transmission be high enough so that disease escapes (susceptible plants that do not become infected) are rare, because escapes can be mistaken for resistant plants leading to inaccurate resistance ratings. Our goal was to learn how environmental conditions influence the efficiency of transmission and to determine what conditions would be best for screening for resistance. The results showed that changes in temperature, light intensity, and day length, but not changes in atmospheric pressure, can significantly affect transmission rates. In general, the greater the light and warmer the temperature (from 20 to 30 C), the better the transmission. We also found that females transmit more efficiently than do males, but the small differences do not warrant sexing of leafhoppers prior to MCDV resistance tests. Thus, although environmental factors significantly affect MCDV transmission efficiencies, these findings will benefit corn breeders and geneticists seeking to understand and improve virus resistance in corn because they show that selecting appropriate conditions (high light levels at temperatures from 25 to 30 C) will reduce disease escapes and allow more reliable screening.
Technical Abstract: The effects of temperature, light intensity, day length, atmospheric pressure, and leafhopper gender on the frequency of transmission of Maize chlorotic dwarf virus (MCDV) by Graminella nigrifrons were evaluated. Transmission rates for both male and female leafhoppers progressively increased from 20 to 30 C. Both males and females tended to transmit at greater frequencies at high light intensities than they did at low, but day length affected the transmission rate only for females at low light intensities. Females were more efficient transmitters than males under most conditions. No significant differences in transmission rates were observed in response to changes in atmospheric pressure. The results showed that the rates of MCDV transmission by G. nigrifrons under conditions typically encountered are sufficiently high so that difficulties caused by disease escapes (uninfected susceptible plants) are minimized.