Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Overwintering biology of Dalbulus leafhoppers (Homoptera: Cicadellidae): adult populations and drought hardiness.

Abstract

Populations of Dalbulus maidis on maize, Zea diploperennis and Tripsacum spp. were monitored weekly with yellow sticky card traps for 18 months in Jalisco, Mexico, during 1989-90. At all sites, the highest catches of adults occurred during the dry season between October and March. In a laboratory study to test the survival of adults without their host plants, significant differences were detected among Dalbulus species. When denied all food and water (absolute drought), species that specialize on maize were more tolerant than those that specialize on Tripsacum spp. Adults reared under environmental conditions simulating the beginning of the wet season (June-reared) were less tolerant of absolute drought than those reared under early dry season conditions (October-reared). When provided with water but no food, October-reared D. maidis lived significantly longer than June-reared D. maidis. Survival of females under water-only conditions was significantly longer than that of males. Field observations revealed that Tripsacum-specializing D. gelbus and D. quinquenotatus overwinter as continuously developing populations on their hosts. In contrast, D. maidis overwinters as active adults that can subsist, at least in part, on free water in the absence of host plants until the summer rainy season begins. Surviving adults then migrate locally to newly planted maize fields.