Persons new to nematode management often look with disdain on the intensive utilization of chemicals. There is a tendency to think that current efforts to develop nonchemical techniques are a new direction in nematode management. A historical perspective, however, shows that early nematologists put considerable effort into developing similar practices prior to the development of the first chemical nematicides.
In retrospect, the development of chemicals was both a blessing and a curse to the science of nematology. It permitted nematologists to demonstrate dramatic differences in crop growth following a chemical treatment. For example, prior to a fumigation , these tuberous Begonias were devastated by lesion nematode, Pratylenchus penetrans. The next year after plants had been removed and the area fumigated with D-D, a profitable crop could be grown.
The negative aspects included a concentration of effort on the development of chemicals and application technology, combined with the view that nematodes did not require as intense a research effort as other pest disciplines. Because of the lack of personnel and resources devoted to nonchemical management techniques, now that the tide of public opinion has turned against the utilization of chemicals, nematodes are increasingly being recognized as a difficult pest to control with nonchemical methods. The two chemicals mentioned so glowingly by Thorne as well as a number of others are no longer available for use in the U.S. because of concerns for groundwater contamination, air pollution, and/or potential for carcinogenicity.