Effects of abamectin on lesser grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), infestation on some stored grains

Abstract

Background: Modern methods of stored wheat grain protection from insect pests strive towards optimizing the use of different techniques and methods within integrated pest management (IPM) programs. One of the methods of integral grain protection is the application of natural originating insecticides. Main body: The potential of the natural origin synthetic insecticide abamectin (a product of soil bacteria, Streptomyces avermitilis fermentation) on the grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), in stored wheat, barley, ray, oats, and triticale was evaluated. The evaluation was conducted in 3 rates. The effects of its application on the infestation of R. dominica on certain physical and chemical traits of cereal grains were examined. The efficacy of abamectin after 7 days of exposure, in all applied dosages, was low (< 56.5% in wheat and < 30.5% in other grains). Abamectin efficacy was significantly increased after 14 days of exposure. R. dominica mortality was 99.0 and 100% after 21-day exposure at the abamectin rates of 0.5 and 1.0 mg kg−1, respectively. Ten weeks after grain treatment, the 3 examined rates prevented the emergence of progeny. The amount of the damaged grains and dockage, as a nus-product of feeding of R. dominica larvae and imago, compared to the untreated, infested sample was significantly smaller, which represents a positive aspect of abamectin application. The application did not change significantly the moisture, protein, and ash contents, in comparison to the control. Conclusion: Positive aspects of the abamectin application on different grain species (wheat, barley, rye, oats, and triticale) caused the highest rates of R. dominica mortality after 21 days of exposure where a total prevention of progeny emergence and absence of changes on technological grain properties occurred.