Biological Control of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae) with fungi from Brazilian Amazon

Stored grains are attacked by insect pests, causing various types of damage and potentially generating economic losses for producers. Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae), popularly known as the red flour beetle, is one of these secondary pests. Thus, the objective of this study was to evaluate the potential of entomopathogenic fungi from the Brazilian Amazon for the control of T. castaneum. To evaluate the control of T. castaneum, different conidial suspensions (105, 106, 107 and 108 conidia/mL) of Beauveria sp. (4.438) and Paecilomyces sp. (4.658) were used, placing 1 mL of each concentration in the center of Petri dish and keeping the insects for 10 min. After that, they were transferred to another Petri dish, incubated for 7 days at room temperature, and Tween 0.01% and NaCl 0.9% solutions were used as negative controls. T. castaneum mortality was obtained only at the highest dilution, 108 conidia/mL, being 22% for the fungus Beauveria sp. (4.438) and 5% for Paecilomyces sp. (4.658). Susceptibility to exposure to abiotic factors was measured with suspensions of Beauveria sp. (4.438) conidia at a concentration of 106 conidia/mL exposed to ultraviolet light for 0, 30, 60 and 120 seconds, and at temperatures of 20, 26 and 32 ºC for 30, 60 and 90 min. The highest germination rate was at 20 °C for 90 minutes, with 92%. The entomopathogenic fungi from the Amazon showed low potential for controlling T. castaneum, however, they may present a higher mortality rate for other insect pests.