Venom from the pupal endoparasitoid, Pimpla hypochondriaca, increases the susceptibility of larval Lacanobia oleracea to the entomopathogens Bacillus cereus and Beauveria bassiana.

Cellular immune responses in insects protect them against parasites and pathogens that enter their hemocoel. Venom from the solitary pupal endoparasitoid, Pimpla hypochondriaca, has previously been shown to suppress certain key, cell-mediated immune responses of Lacanobia oleracea. Experiments were performed to determine if L. oleracea larvae injected with P. hypochondriaca venom would be more susceptible to Bacillus cereus, or Beauveria bassiana, when these microorganisms were subsequently injected. Mortality due to B. cereus (approximately 15 colony-forming units [CFU]/larva) and B. bassiana (approximately 2.4 x 10(3) conidia/larva) was enhanced by prior injection of 4 microg of venom. In addition, injection of venom/Dulbecco's phosphate-buffered saline (DPBS) or DPBS/B. bassiana reduced the rate at which larvae gained weight compared to control larvae. However, the greatest reduction in weight was recorded for larvae that had been injected with venom/B. bassiana conidia.