Insecticidal response of the understudied Latheticus oryzae to six insecticides

ABSTRACT Latheticus oryzae is a cosmopolitan secondary pest of stored products that has received limited attention, despite being capable of causing quantitative and qualitative losses. The objective of this study was to assess the efficacy of six contact insecticides, α-cypermethrin, λ-cyhalothrin, deltamethrin, etofenprox, pirimiphos-methyl, and piperonyl butoxide + acetamiprid + d-tetramethrin, against both adults and larvae of L. oryzae. The experiment was conducted on cement surfaces at three doses, in the absence and presence of food, over specific exposure intervals (1, 3, 5, and 7 days). A total of 1512 adults and 1512 larvae were used for the experiment. Pirimiphos-methyl, λ-cyhalothrin, and α-cypermethrin, at recommended doses caused the highest adult mortality, while larvae were generally less affected by most tested insecticides, compared to the adults. Among the six insecticides, pirimiphos-methyl proved to be the fastest acting compound, inducing significant adult mortality on the first day of the trials. Food presence significantly reduced insecticidal efficacy across all treatments. These findings highlight stage-specific susceptibility and provide insights for optimizing stored-product pest management strategies.