Entomopathogenic nematodes (EPN) are environmentally friendly biological control organisms that are used to control insect pests, especially soil-dwelling insects, such as the larval stage of the small hive beetle, a serious pest of honeybee hives.

The EPN invade the host larva to reproduce and ultimately kill the host, thus providing a pesticide-free control option. To improve EPN production for commercial use, Agricultural Research Service (ARS) researchers and Southeastern Insectaries, Inc. (SEI), a commercial EPN supplier, partnered to improve production efficiency using live insects as the host for in vivo production.

Production of EPN in live insect hosts has several advantages over in vitro production methods using fermentors. These advantages include a smaller initial investment in equipment; the ability to produce more nematode species; and a higher virulence of nematodes produced. Techniques were developed to lower the costs of in vivo nematode production by developing a mechanized process for insect host production and nematode inoculation.

The EPN invade the host larva to reproduce and ultimately kill the host, thus providing a pesticide-free control option.

Mealworms (Tenebrio molitor) were chosen as the insect host for the EPN because there were existing commercial methods for their production. Nematode-infected mealworm larvae have a better structural integrity than other hosts. Another development was an automatic larval sorting system for nematode inoculation. A mass nematode inoculation system was created, which allowed the simultaneous inoculation of thousands of larvae.

The work covered by this project has significantly impacted the field of biological insect control through the development of several new methods of large-scale insect rearing. Furthermore, based on the technology developed, high-quality nematode biocontrol products are now being sold by SEI. Significant sales have been made to the beekeeper industry and for control of various turf pests.

Moderate sales for the control of pests in other commodities have also been accomplished. SEI reports that as a result of the technology developed and transferred from this project, it has become a profitable business, with nematode sales increasing regularly. The estimated annual sales of nematodes are $250,000, approximately 80% of total sales. Annual sales of mealworm larvae for feed are approximately $100,000, and they continue to increase. This technology has benefited the public at large because there is no other efficacious way to control this honey bee pest.