Influence of aphid-specific pathogen Conidiobolus obscurus on population dynamics of bamboo aphids and the aphid-control effect

Abstract

To determine the regulation of Conidiobolus obscurus on population dynamics of four species of bamboo aphids, specifically, Metamacropodaphis bambusisucta, Takecallis taiwanus, Melanaphis bambusae, and Takecallis arundinariae, three temperature-photoperiod regimes of 20-28 ℃ were used along with 12-15 h of light. Results showed that C. obscurus inhibited bamboo aphid populations with the temperature-photoperiod regimes. Data fit models well with C. obscurus-inoculated groups fitting to log-logistic models and the control groups fitting to logistic models. Results also showed outbreak characteristics of population dynamics for healthy aphids with peak aphid densities 18.4-139.2 times larger than initial densities. Especially in the first observation week, bamboo aphids infected with C. obscurus inhibited population development with the number of days needed to double population densities being ten times more than healthy aphid populations. Thus, C. obscurus could help regulate host populations, delay the occurrence of the bamboo aphid population peaks, and provide potential aphid control in bamboo forests.