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

Resumen

Rhyzopertha dominica (F.) is a major pest in stored cereals in Colombia, which causes significant losses
in production. Chemical control is the main tool used in the country, and despite the common use of
insecticides such as deltamethrin, resistance has been observed in some Colombian 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. Failure
to control and survival tests showed that the recommended doses on product labels were insufficient to
protect the grain from this pest. Failure control demonstrated that 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 suggest that R. dominica may be developing resistance to insecticides,
as has been found in other countries. This underscores the importance of conducting toxicological studies and the need to investigate molecules with diverse modes of action, contributing to the strengthening of
chemical management strategies. To achieve effective control, it is necessary to implement Integrated
Pest Management (IPM) with a focus on alternative methods to chemical control.