Differential susceptibility of Popillia japonica 3rd instars to Heterorhabditis bacteriophora (Italian strain) at three different seasons

ABSTRACTThe scarab beetle Popillia japonica, a pest native to northern Japan, has been recently found in Italy. Entomopathogenic nematodes are useful for biological control of this invasive insect. Previous work showed that 1st and 2nd larval stages are more susceptible to nematodes than 3rd instars. We tested the effectiveness of Heterorhabditis bacteriophora in the laboratory against P. japonica 3rd instars. Experiments were conducted in Italy with larvae field collected in the fall, winter and spring, showing a significant decrease in effectiveness from the fall to spring.