Effect of maize stunting mollicutes on survival and fecundity of Dalbulus leafhopper vectors

Abstract

S U M M A R YThe effect of corn stunt spiroplasma (CSS) on survival and fecundity of three Dalbulus leafhopper species was determined. CSS significantly reduced the survival, as measured by the time to 50% ([SO) and 25% ( I~~) survival, and by the scale parameter ( b ) of the Weibull model, for D. elimatus and D. gelbus. Fecundity of these two species, as measured by the net and gross reproductive rates, was also reduced by CSS. CSS did not significantly affect the corn leafhopper, D. maidis. In a separate experiment, maize bushy stunt mycoplasma (MBSM) reduced the survival and fecundity of D. maidis at temperatures from 20 to 29°C. The effect of MBSM on D. maidis survival was less severe than CSS on D. elimatus and D. gelbus; t 2 5 , but not t50, was reduced by MBSM. Survival times and the cohort generation time generally declined with increasing temperature. Fecundity, however, generally increased with increasing temperature. 0

Interactions of maize bushy stunt phytoplasma with the leafhopper vector, <i>Dalbulus maidis</i> (Delong and Wolcott) (Hemiptera: Cicadellidae) and associated microbiota

“…This is in contrast to the observed in other studies, where maize bushy stunt phytoplasma (maize bushy stunt mycoplasma or MBSM in the original document) reduced the survival, life span of adults, fecundity and net reproductive rate (Ro), but not the intrinsic rate of increase (rm) of D. maidis when compared with the corn stunt spiroplasma and control treatments at temperatures from 20 to 29 °C (MADDEN et al, 1984).…”

Influences of Temperature onHomalodisca vitripennis(Hemiptera: Cicadellidae) Survival Under Various Feeding Conditions

“…To estimate exposure time to 50% mortality (LT 50 ), the survivorship curve at each temperature was described by using the Weibull model (Madden et al 1984):…”

Phytoplasmas: bacteria that manipulate plants and insects

“…Phytoplasmas may or may not affect the fitness and survival of insect vectors. Some leafhopper species are negatively impacted by the phytoplasma infection as they die around the time they are capable of inoculating plants with the phytoplasmas, whereas other leafhopper species do not show obvious negative effects from the infection and sometimes can even benefit from the phytoplasma infection by living longer when deprived of a main food source and when exposed to lower suboptimal temperatures (Ebbert and Nault, 1994; Madden and Nault, 1983; Madden et al ., 1984). The better adaptation of some leafhopper species to phytoplasma infection is, at least in the case of Dalbulus leafhopper spp., MBSP and S. kunkelii , a result of a long history of association between the organisms (Nault, 1990).…”