INSECTICIDAL EFFECT OF FENITROTHION, DIATOMACEOUS EARTH AND BEAUVERIA BASSIANA AGAINST COLEOPTERAN PESTS ON STORED GRAIN

G M. DAL BELLO; C FUSE; M P. JUÁREZ; N. PEDRINI; A. IMAZ; S. PADIN

Campobasso, Italia

Congreso; IOBC Conference - Integrated Protection of Stored Products . IOBC/WPRS (OILB/SROP); 2009

International Organization of Biological Control

INSECTICIDAL EFFECT OF FENITROTHION, DIATOMACEOUS EARTH AND BEAUVERIA BASSIANA AGAINST COLEOPTERAN PESTS ON STORED GRAIN Gustavo DAL BELLO1, Cecilia FUSÉ2,3, Patricia JUÁREZ3, Nicolás PEDRINI3, Augusto IMAZ1, Susana PADÍN2 1Comisión de Investigaciones Científicas Provincia de Buenos Aires y CIDEFI, Facultad de Ciencias Agrarias y Forestales, UNLP, calle 60 y 119 La Plata, Argentina. 2Cátedra de Terapéutica Vegetal, Departamento de Ambiente y Recursos Naturales, Facultad de Ciencias Agrarias y Forestales, UNLP. 3Instituto de Investigaciones Bioquímicas de La Plata, CONICET, Facultad de Ciencias Médicas, UNLP, calle 60 y 120 La Plata, Argentina. Abstract Pest insects of stored grains can cause losses in weigth, quality, commercial value and germinative power of seeds. Toxicity and protectant potential of a chemical and two biological insecticides against two major stored-grain beetle species: Tribolium castaneum (Herbst) and Rhyzopertha dominica (Fabricius) were investigated in the laboratory. The organophosphate fenitrothion at 100% and 50% of the labeled rate, and two biological insecticides: diatomaceous earth (DE) at 3000 ppm and the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin (Hyphomycete) at 1 mL/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 synergism 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 storage weevils. IOBC Conference - Integrated Protection of Stored Products . IOBC/WPRS (OILB/SROP). Campobasso (Italia), June 29- July 2, 2009.