The potential of novel phenol-derivative compounds for feeding deterrent control of several stored-product coleopteran pests

The development of new tactics for the management of stored-product insects is important as more conventional methods may becoming less effective due to pesticide resistance and the increasing interest in developing chemical control options with fewer of the negative side effects (e.g., environmental and health impacts). I screened several libraries of phenol-derived compounds with varying substitutions and substituents for their potential as feeding deterrents and insecticides using flour disk no-choice feeding bioassays against a total of five species of stored-product coleopteran: Tribolium castaneum, T. confusum, Sitophilus oryzae, S. zeamais, and Rhyzopertha dominica. By using structurally similar compounds, I was able to determine some structure-activity relationships, in particular meta- and para-substituted rings with mid-sized substituents showed the highest feeding deterrent activity. I was also able to show that while there where some similarities in both feeding behavior and mortality between the closely related species, there were also differences which highlights the importance of not extrapolating behavior even to closely related species. There was also evidence that, in general, the primary pests (S. oryzae, S. zeamais, and R. dominica) showed more sensitivity to the test compounds compared to the secondary pests (T. castaneum and T. confusum), which may be explained by looking at these species as specialist and generalist feeders. Finally, during the course of the experiments, an alternative method of measuring feeding in the flour disk bioassays was developed (surface area) and compared to the established method (weight). The methods are comparable and surface area analyses may be a less expensive, alternative way of measuring feeding in some scenarios. Ultimately I was able to identify several compounds that show potential to be feeding deterrents for some stored-product coleopteran pests without significant mortality.