Lesser mealworm (Alphitobius diaperinus) association with Enterococcus cecorum and pest management considerations for this pest in broiler houses

Abstract

The lesser mealworm Alphitobius diaperinus is a worldwide pest of poultry. Lesser mealworms transmit various viral and bacterial pathogens. The economic impact of the beetle is a problem for broiler growers. Consumption of the beetle by young birds leads to reduced weight gain and gastrointestinal issues. The boring out of insulation by the larvae to prepare a pupation site reduces the insulating abilities and increases energy costs. This study indicates that the lesser mealworm is a mechanical vector for the causative agent of enterococcus spondylitis (ES) disease in poultry. With 30 min of exposure to Enterococcus cecorum inoculated agar, the lesser mealworm was able to transfer bacteria phenotypically similar to E. cecorum to sterile agar plates within 30 min of exposure. Future research should expand beyond mechanical transmission to determine the vector competency of this pest to E. cecorum. A new set of primers was developed for detection of E. cecorum by use of PCR. A Knowledge, Attitudes, and Practices (KAP) survey was conducted on broiler growers in one county of Oklahoma. Eighty-three percent of growers observed A. diaperinus present in their broiler houses. Ninety-two percent of growers monitor their houses for pests. Fifty-eight percent of the growers targeted beetles for their insecticide treatments, mostly targeting under feeders and along the walls. Our study reveals that 67% of growers windrowed their litter. Beetles were exposed for a sublethal amount of time (LT20) to various insecticide formulations. The fecundity and hatched larvae were counted over 30 d beginning 3 wk after sublethal insecticide exposure. Mean number of eggs by treatment was highest in the first 6 d of the experiment. No insecticide treatment had less eggs or larvae than the control in this experiment, and some treatments had significantly greater numbers of eggs and larvae. On days 0-6, Onslaught (Esfenvelerate) had the greatest mean of 31.75 eggs per mating pair and control had the least with a mean of 6.94 eggs per mating pair. More research is needed to determine if the increase in fecundity observed will result in an increase in population rate.