An Assessment of Progress toward Microbial Control of Plant-Parasitic Nematodes.

In recent years, continuing environmental problems associated with the use of nematicides (47) have introduced a sense of urgency into the search for alternative methods of nematode management. For the past 90 years, research on the biological control of nematodes with microbial agents has been done by a few dedicated nematologists who have worked in small groups with little support. About 10 years have passed since it was recognized that in some soils nematode multiplication was suppressed by nematophagous fungi. For the first time, biological agents were shown to provide longterm effective control of cyst (29) and rootknot nematodes (45) in the field. However, this control had developed fortuitously in soils and did not result from the release of an agent. At about the same time, a French company produced the first commercial biological control agent for nematodes based on a nematode-trapping fungus (10). The optimism that resulted from these developments has led to a considerable increase in research effort, but unfortunately