Harmful effects on Oryzaephilus surinamensis (L.) andTribolium castaneum by food grade antioxidants and their formulations in peanut kernels

GARCÍA, D.; PASSONE, MARÍA A.; GIRARDI, N.S.; NESCI, A.; ETCHEVERRY, M.

San Miguel de Tucuman

Congreso; XII Congreso argentino de microbiologia general; 2017

Two important species of pest insects are Oryzaephilus surinamensis (L.) saw-toothed grain beetle (Coleoptera; Silvanidae) and Tribolium castaneum, Herbst; the red flour beetle (Coleoptera; Tenebrionidae) which attack grains, preferring stored cereal products and oleaginous seeds. Both insects could acts as vector for potential toxigenic molds as Aspergillus spp. and the constant migration of insect populations within granary ecosystem efficiently contributes to dispersion of viable fungal spores which are carried on the vector?s body surface or are deposited with its feces. For this, the aim of this study was to investigate the effect of two food grade antioxidant as 2(3)-tert-butyl-4 hydroxyanisole (BHA) and 2,6-di(tert-butyl)-p-cresol (BHT) frees and microencapsulated on mortality, body weight and total protein content of Oryzaephilus surinamensis (L.) and Tribolium castaneum. The effect of free BHA and BHT and their formulations (F-BHA and F-BHT) at dose ranging from 10 to 45mM, in peanut kernel was evaluated. BHA and BHT free antioxidants showed significant mortality percentages upper than 80%. Besides, microencapsulated antioxidants at 20 and 30 mM significantly affected the survival of insect populations after 45 days of exposure. Insecticidal activities of BHA andBHT formulations were estimated in 100 and 70%, respectively. Insect weight was significantly affected by all studied treatments and the major effect on O. surinamensis (L.) was produced by time, especially with the application of BHA follow by F-BHA and F-BHT. Body mass weight of T. castaneum showed the highest reduction after application of F-BHA, followed F-BHT, BHT and BHA. Total proteincontent of insects also was affected by both free and microencapsulated antioxidants. Formulations preserved insecticidal effectiveness of antioxidants and extended their effect for up to 45 days which could act as new strategies to control these insects pest. Besides, sub-lethal levels of these compounds results in a loss of insects? weight and change in protein content. These results showed the first step in toxicity mechanisms for free and microencapsulated BHA and BHT on O. surinamensis (L.) and T. castaneum, the two important aflatoxin fungi vectors in peanut agro-ecosystems.