Pandora neoaphidis overwintering had been investigated by monitoring its prevalence in Myzus persicae populations in open fields. Cabbage plants in field plots were weekly taken after mycosis initiation, to count and examine the living and dead aphids infected by P. neoaphidis. Based on the field data, infection levels (I) varied with field temperature (T), relative humidity (RH) and aphid count (numbers of living aphids per plant, N) over days (D), fitting well to the modified logistic equation I=0.91/[1+exp(8.5+(2.0H T H RH-20.2NI0)D)] (r²=0.897), where H T indicated daily hours of low temperature (<4°C), H RH daily hours of high air humidity (>90% RH) and I0 primary infection level. The model demonstrated the abiotic and biotic factors... |