Different host plant species modifies the susceptibility of Bactericera cockerelli to the entomopathogenic fungus Beauveria bassiana

Bactericera cockerelli (Sulc.) is a serious pest of solanaceous crops and a vector of the plant pathogen Candidatus Liberibacter psyllaurous. Entomopathogenic fungi are the most important biological control alternatives for this pest. Host plant species, however, can modify the outcomes of insect–pathogen interactions. We conducted laboratory experiments to quantify the virulence of two isolates of the entomopathogenic fungus Beauveria bassiana (Bals. [Vuill.]), BB40 and BB42, against third instar B. cockerelli nymphs maintained on chilli pepper plants. Owing to the lack of difference in virulence against B. cockerelli nymphs on chilli pepper between the two B. bassiana isolates, only BB42 was used to: compare virulence against nymphs maintained on either chilli pepper, potato or tomato; and in vivo conidia production from nymphs maintained on different host plants. Virulence of the two B. bassiana isolates against B. cockerelli nymphs was similar. Bactericera cockerelli nymphs maintained on tomato were more susceptible to B. bassiana than nymphs maintained on potato or chilli peppers. Infected nymphs maintained on chilli peppers produced the greatest number of conidia followed by infected nymphs maintained on tomato and potato. Host plant affected the susceptibility of B. cockerelli to B. bassiana isolate BB42 and subsequent conidia production. The implications of our results for microbial control of B. cockerelli by B. bassiana are discussed.