Mortality of various lepidopteran larvae infected by New Zealand <i>Zoophthora radicans</i> isolates from different hosts

Abstract

Zoophthora radicans an entomophthoralean fungus is a potential biocontrol agent for a wide range of insect pests The mortality of six insect species inoculated with twelve Z radicans isolates from different hosts found in New Zealand was evaluated using a bioassay Zoophthora radicans isolates originating from the host being tested were generally but not always more effective than isolates originating from other species For example lightbrown apple moth (LBAM) was highly susceptible to isolates Z2 and Z6 from leafrollers (96 and 89 mortality respectively) but was not susceptible to any isolates from diamondback moth (DBM) (mortality lt;5 Plt;0001) DBM was highly susceptible to all isolates from DBM (gt;96 mortality) but only moderately susceptible to leafroller isolates (lt;66 Plt;0001) Although resting spore production was low overall some isolates produced more resting spores in certain hosts such as Z2 and Z6 in LBAM (Plt;0001) and Z8 and Z5 in DBM (Plt;005)