Dietary stress increases the susceptibility of Tribolium castaneum to Beauveria bassiana

Certain stresses increase insects’ susceptibility to fungal Beauveria bassiana. Restriction of access to food by sanitation is an important stress-inducing means of insect management. Similarly, the nutrition content of various foods is a determinant of insect vigor and success on different commodities. This study investigated the effect dietary stress on the efficacy of B. bassiana for the red flour beetle Tribolium castaneum. When beetle larvae were deprived of food various periods of time they were more susceptible to fungal infection than when provided a constant food supply. Larvae that were reared on a rice diet were more susceptible than those reared on wheat flour. The addition of protease inhibitors to flour also increased fungal efficacy. Dietary stress, whether by food deprivation or suboptimal food quality significantly affected developmental rate and efficacy of B. bassiana.