Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Comparative growth and spatial distribution of Dalbulus leafhopper populations (Homoptera: Cicadellidae) in relation to maize phenology.

Abstract

The population growth and spatial distribution of 3 species of Dalbulus were monitored on maize from the seedling stage through to maturation and senescence under greenhouse conditions. D. maidis, a maize specialist, completed 2 generations before maize senescence, with a significant population increase between the 1st and 2nd generations. F1 nymphs and adults moved upward on leaves (vertically) and from outer leaves into whorls (horizontally) soon after eclosion. D. gelbus, a gamagrass (Tripsacum, wild maize relative) specialist also found on maize in the field, completed 2 generations on maize, but with a significant decrease in population size between generations. D. gelbus moved upward on leaves as F1 nymphs and adults, but not into whorls as frequently as D. maidis. D. quinquenotatus, a gamagrass specialist, produced one generation on maize, with population extinction occurring soon after adult eclosion on post-anthesis maize. Nymphs and adults remained within protective leaf sheaths of lower leaves, and did not move upward on leaves or into whorls. Some individuals moved onto tillers developing at the base of maize stalks. Utilization of the whorl is suggested to be critical in establishing a large 2nd generation before maize senescence. Differences in the behavioural responses of Dalbulus species to maize phenology may explain, in part, the observed field host associations, and influence pest potential of Dalbulus species.