Quality Assessment of Commercially Produced Entomopathogenic Nematodes

The quality of the most widely commercialized entomopathogenic nematodes, Steinernema carpocapsae (Weiser) and Heterorhabditis bacteriophora Poinar, was assessed from 30 shipments from six United States suppliers mailed to three locations. These suppliers comprise a cottage industry aimed in large part at a mail-order market. Most companies were accessible and reliably shipped pure populations of the correct species on time, in sturdy containers, and often with superb accompanying instructions. Nematodes were received in satisfactory condition with acceptable levels of viability. Consistency, however, was a problem, with each supplier having one or more weak spots to bolster. Most shipments did not contain the expected nematode quantity, and one shipment had no nematodes. Pathogenicity of several products against Galleria mellonella (L.) larvae was not equivalent to our controls. H. bacteriophora was not always available when ordered. A few products contained mixed populations of both nematode species. Application rate recommendations provided by some suppliers appeared unsound. We conclude that (1) the entomopathogenic nematode cottage industry lacks rigorous quality control, (2) self-regulation is problematic without feedback on quality, and (3) consumers are rarely able to provide this feedback. Improved reliability by the nematode industry will most likely be achieved via industry-generated agreement on standards for quality.