Insecticidal effect of fenitrothion, diatomaceous earth, and Beauveria bassiana against Coleopteran pests on stored grain

DAL BELLO GUSTAVO M; FUSE CECILIA B; JUÁREZ M PATRICIA; PEDRINI NICOLAS; IMAZ AUGUSTO

Integrated Protection of Stored Products. IOBC-WPRS Bulletin.

International Organization for Biological and Integrated Control of Noxious Animals and Plants, West Palearctic Regional Section (IOBC/WPRS)

Lugar: Darmstadt; Año: 2011; p. 175 - 180

Abstract: Pest insects of stored grains can cause losses in weight, quality, commercial value and seed germination. Toxicity and protectant potential of a chemical and two biological insecticides against two major stored-grain beetle species: Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.) were investigated in the laboratory. The organophosphate fenitrothion at 100% and 50% of the labelled rate, and two biological insecticides: diatomaceous earth (DE) at 3000ppm and the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes) at 1ml/kg grain of water suspension (1 x 108 conidia/ml), were applied both or combined on hard wheat grain. For grains bioassayed after 14 days of storage following chemical treatment at least 98% mortality was obtained in T. castaneum and R. dominica even with the lowest dose. For both insect species DE powder + B. bassiana formulations showed a mortality significantly higher than each biological insecticide alone. When T. castaneum and R. dominica were exposed to B. bassiana or DE, the mortality means were 2% and 45% respectively, but when the weevils were treated with both the fungus and DE, there were 20% mortality for T. castaneum and 54% for R. dominica. The results suggest that additive effect was evident for the fungus-diatomaceous earth combination and the application of B. bassiana and DE may be a way to overcome some of the constraints of virulence on fungal entomopathogens as biocontrol agents against stored-product insect species. B. bassiana formulations showed a mortality significantly higher than each biological insecticide alone. When T. castaneum and R. dominica were exposed to B. bassiana or DE, the mortality means were 2% and 45% respectively, but when the weevils were treated with both the fungus and DE, therewere 20% mortality for T. castaneum and 54% for R. dominica. The results suggest that additive effect was evident for the fungus-diatomaceous earth combination and the application of B. bassiana and DE may be a way to overcome some of the constraints of virulence on fungal entomopathogens as biocontrol agents against stored-product insect species.Pest insects of stored grains can cause losses in weight, quality, commercial value and seed germination. Toxicity and protectant potential of a chemical and two biological insecticides against two major stored-grain beetle species: Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.) were investigated in the laboratory. The organophosphate fenitrothion at 100% and 50% of the labelled rate, and two biological insecticides: diatomaceous earth (DE) at 3000ppm and the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes) at 1ml/kg grain of water suspension (1 x 108 conidia/ml), were applied both or combined on hard wheat grain. For grains bioassayed after 14 days of storage following chemical treatment at least 98% mortality was obtained in T. castaneum and R. dominica even with the lowest dose. For both insect species DE powder + B. bassiana formulations showed a mortality significantly higher than each biological insecticide alone. When T. castaneum and R. dominica were exposed to B. bassiana or DE, the mortality means were 2% and 45% respectively, but when the weevils were treated with both the fungus and DE, there were 20% mortality for T. castaneum and 54% for R. dominica. The results suggest that additive effect was evident for the fungus-diatomaceous earth combination and the application of B. bassiana and DE may be a way to overcome some of the constraints of virulence on fungal entomopathogens as biocontrol agents against stored-product insect species. B. bassiana formulations showed a mortality significantly higher than each biological insecticide alone. When T. castaneum and R. dominica were exposed to B. bassiana or DE, the mortality means were 2% and 45% respectively, but when the weevils were treated with both the fungus and DE, therewere 20% mortality for T. castaneum and 54% for R. dominica. The results suggest that additive effect was evident for the fungus-diatomaceous earth combination and the application of B. bassiana and DE may be a way to overcome some of the constraints of virulence on fungal entomopathogens as biocontrol agents against stored-product insect species.