INTEGRATION AND PROTECTION OF NOVEL NEMATODE MANAGEMENT STRATEGIES

Development of novel nematode control strategies is being pursued by determining the molecular bases for factors influencing or regulating nematode-plant interactions and nematode responses to biotic and abiotic factors outside the host plant. Manipulation of the normal processes by disruption or modification should lead to control strategies. Some of these include virulence/avirulence and resistance/susceptibility interactions, and fundamental determinants of parasitic ability, such as nematode-induced modifications to host cellular and physiological processes. Advances will provide novel forms of resistance in plants and potentially the wide application of cloned, natural resistance genes. Other strategies will be based on disruption or modification of life-history events such as molting, mating, egg laying, egg hatch, attraction to roots, ability to survive outside the host (e.g. processes of dormancy, diapause, cryptobiosis), and on susceptibility to parasites and predators that may themselves be modified to enhance nematode control. Many of these potential controls will require considerable investment; neither their genetic stability nor their impact on the genetics of nematodes will be known. Integration of novel strategies into management programs that utilize existing and other novel control options will be necessary to maximize their long-term effectiveness. Some possibilities for their deployment in integrated programs are discussed in relation to potential effects on nematode initial population densities and seasonal multiplication rates, and on the tolerance of transgenic resistant crop plants. The application of molecular and biochemical diagnostic techniques to differentiate nematode groups of practical consequence at the pathotype, species and genus levels is discussed.