Control failure of deltamethrin in Colombian populations of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

Resumo

Rhyzopertha dominica (F.) is a major pest in cereals stored in Colombia, which causes significant losses. Chemical control is the main tool used in the country, but only two insecticides are registered. Despite the common use of insecticides, such as deltamethrin, resistance has been observed in some local populations but is a worldwide problem. The objective of this work was to evaluate the efficacy of deltamethrin and the combination of deltamethrin and piperonyl butoxide in Colombian populations of R. dominica. Laboratory rearing of insects preceded failure to control and survival tests, revealing that the recommended doses on product labels were insufficient to protect the grain from this pest. Failure control was found because mortality did not exceed 80 percent in the populations studied. Differences in susceptibility were observed between populations, with El Espinal and Neiva highlighted as less susceptible and Pore as the most sensitive to the action of insecticides. The combination of deltamethrin and piperonyl butoxide reduced insect survival but did not effectively control it (0%–20%). These results suggested that R. dominica may be developing resistance to insecticides, as had been found in other countries. This, in turn, would contribute to strengthening chemical management strategies. To achieve effective control, it is necessary to implement Integrated Pest Management (IPM), with a focus on alternative methods.