ALLELOCHEMICALS AS BIOPESTICIDES FOR MANAGEMENT OF PLANT-PARASITIC NEMATODES

Many allelopathic compounds in their native or processed forms have potential for development as viable components of plant-parasitic nematode management strategies. Allelochemicals have been identified that possess differing levels of activity against a wide range of plant-parasitic nematodes. In general, these compounds are less toxic to nontarget species, and less persistent in soil than chemical nematicides. Operative mechanisms for plant-parasitic nematode control with allelopathic compounds include nematicidal activity, nematostatic activity, and nematode behavior modification. Allelochemicals are sometimes produced in large quantities in plant material or as agricultural waste, making the use of rotation crops, cover crops, and organic amendments effective means for production and/or distribution of the active compounds. A greater understanding of the effects of soil microbes and environmental conditions on allelopathic compounds is necessary to improve their efficacy for control of parasitic nematodes. Use of allelochemicals for nematode control will require that growers know specifically what types and population levels of nematodes are present in their production fields. Development of improved production and incorporation methods for rotation and green manure crops, and appropriate application methods for processed allelochemical compounds, will also enhance the efficacy and consistency of these compounds for nematode control.