ARS | Publication request: Assessing effects of esfenvalerate aerosol applications on resident populations of Tribolium castaneum (Herbst), the red flour beetle, through direct and indirect sampling

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2012
Publication Date: February 15, 2013
Citation: Arthur, F.H., Campbell, J.F., Fontenot, E.A., Toews, M.D. 2013. Assessing effects of esfenvalerate aerosol applications on resident populations of Tribolium castaneum (Herbst), the red flour beetle, through direct and indirect sampling. Journal of Stored Products Research. 53: 1-6. http://dx.doi.org/10.1016/j.jspr.2012.12.007.

Interpretive Summary: Aerosol insecticides are used to control red flour beetles in flour mills, but there is little information on how these aerosols affect resident beetle populations. We conducted studies by placing food (flour) containing different life stages of beetles underneath metal shelves inside small sheds. The sheds were either untreated or sprayed every 2 or 4 weeks with the labeled rate of the pesticide esfenvalerate, trade name Conquer. The aerosol treatments did not affect the population development in the flour. However, there were more dead beetles in the treatments compared to the controls, and more live beetles in pheromone traps in the controls compared to the treatments. Results show that although the aerosol applications reduced overall insect numbers, the presence of available food material allowed for continued population development.

Technical Abstract: Small-scale field sheds were infested with resident populations of the red flour beetle, Tribolium castaneum (Herbst), and either left untreated or treated every two or four weeks with an aerosol spray of esfenvalerate (Conquer ®). The sheds were infested by placing flour food patches underneath shelves in the shed, and two trials were done in separate blocks. Aerosol efficacy was assessed using pheromone traps to estimate live adults (indirect sampling) and by collecting dead adults and estimation of eggs, larvae, pupae, and adults in the food patches (direct sampling). Beetle populations readily colonized the food patches, and overall populations of each life stage in the food patches were similar in the controls and in the 2- and 4-week aerosol treatments. However, the proportion of individuals in the egg and larval stages was greater in the control versus the aerosol treatments. There were more live adults trapped in the controls than in the aerosol treatments, with lower adult numbers in the two-week aerosol spray than in the four-week sprays, and more dead adults in the food patches in the control and 4-week spray than in the 2-week spray. There were more adults in the pheromone traps in the untreated controls relative to the aerosol treatments, with more in the four-week than in the two-week aerosol treatment, but no differences in dead adults. Indirect sampling using pheromone traps gave consistent indications of aerosol efficacy, regardless of the extent of food patch colonization, but the presence of dead adults could not be used reliably as in indicator of treatment efficacy. The presence of the food patches allowed continued population development, and as a result the frequency of aerosol application had little impact on overall populations in the food patches.