Insecticidal properties of etofenprox for the control of Ephestia kuehniella, Rhyzopertha dominica, Sitophilus oryzae, and Tribolium confusum on stored barley, maize, oats, rice, and wheat

Abstract

Etofenprox is a novel pyrethroid insecticide that targets the nervous system of insects by affecting the function of the sodium channel. The current study examines the insecticidal activity of etofenprox against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae, Rhyzopertha dominica (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (Coleoptera: Curculionidae) adults, and Tribolium confusum (Coleoptera: Tenebrionidae) adults and larvae on different grain commodities. For this purpose, etofenprox was applied on barley, maize, oats, rice, and wheat at 0.1, 1, 5, and 10 ppm. Mortality levels were recorded after 7, 14, and 21 days of exposure. For E. kuehniella larvae, 10 ppm applied on whole rice killed 96.1% of the exposed individuals after 21 days of exposure. The application of etofenprox on oats at 5 ppm caused the death of 98.3% of the exposed R. dominica adults. Complete mortality was observed for R. dominica adults 21 days post-exposure to oats and whole rice treated with 10 ppm etofenprox. The highest concentration applied on barley caused 95.0% mortality to S. oryzae adults, while the same concentration on maize killed 76.8% of T. confusum adults after 21 days of exposure. Larvae of T. confusum exhibited high mortality levels reaching 99.4% after 21 days of exposure to barley treated with 10 ppm etofenprox. Progeny production of parental R. dominica adults was almost suppressed on all commodities treated with 5 ppm etofenprox. The offspring emergence of S. oryzae ranged between 4.4 and 24.6 adults per vial at 10 ppm. No T. confusum progeny was produced at 10 ppm etofenprox. Our results document that etofenprox is highly effective as grain protectant against several insect species, their developmental stages and their progeny production, but its performance depends on the type of the commodity that it is applied on.

Keywords: Bostrychidae; Curculionidae; Mortality; Progeny; Pyralidae; Pyrethroid insecticide; Tenebrionidae.