12 Jul 2002 9:39 AR AR165-PY40-09.tex AR165-PY40-09.SGM LaTeX2e(2002/01/18) P1: GJC 10.1146/annurev.phyto.40.032602.130045 Annu. Rev. Phytopathol. 2002. 40:221–49 doi: 10.1146/annurev.phyto.40.032602.130045 PHYTOCHEMICAL BASED STRATEGIES FOR NEMATODE CONTROL David J. Chitwood Nematology Laboratory, USDA-ARS, Building 011A, BARC-West, Beltsville, Maryland 20705; e-mail:
[email protected] Key Words nematicide, natural product, anthelmintic, biological control, fungi ■ Abstract This review examines the discovery of naturally occurring phytochem- icals antagonistic toward plant-parasitic and other nematodes. Higher plants have yielded a broad spectrum of active compounds, including polythienyls, isothiocyanates, glucosinolates, cyanogenic glycosides, polyacetylenes, alkaloids, lipids, terpenoids, sesquiterpenoids, diterpenoids, quassinoids, steroids, triterpenoids, simple and com- plex phenolics, and several other classes. Many other antinematodal compounds have been isolated from biocontrol and other fungi. Natural products active against mam- malian parasites can serve as useful sources of compounds for examination of activity against plant parasites. The agricultural utilization of phytochemicals, although cur- rently uneconomic in many situations, offers tremendous potential. INTRODUCTION Phytoparasitic nematodes are among the most notoriously difficult crop pests to control. Historically, management of nematode-induced crop damage has been achieved with the utilization of plant resistance, crop rotation and other cultural practices, or chemical nematicides. Two groups of chemical nematicides predomi- nate: low-molecular-weight soil fumigants and contact carbamates or organophos- phates (13, 170). The development of new nematicides is a difficult task. Because most plant- parasitic nematode species spend their lives in the soil or within plant roots, the target of any chemical nematicide often resides at a fair distance away from the site of application of the chemical.