Challenges in developing phytochemicals for use as nematode management agents

Authors: Chitwood, David; Meyer, Susan

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2013
Publication Date: 8/25/2013
Citation: Chitwood, D.J., Meyer, S.L. 2013. Challenges in developing phytochemicals for use as nematode management agents [abstract]. International Congress of Plant Pathology Abstracts and Proceedings. 43:379.

Interpretive Summary:

Technical Abstract: Plants and fungi produce diverse classes of chemicals toxic or otherwise antagonistic to nematodes. Because phytochemicals are often safer than synthetic compounds and consequently receive less regulation, researchers are actively engaged in development of these materials as components of management systems for plant-parasitic nematodes. Unfortunately, actual utilization in agriculture has remained problematic for several reasons. Often the cost of purifying or synthesizing rather complex molecules has impeded utilization; low toxicity toward nematodes has sometimes resulted in impractical quantities required for application. Moreover, many of the same hurdles facing the development of new synthetic chemical nematicides confront nematicidal phytochemicals. In addition to acceptable target specificity, the ideal compound should migrate in soil sufficiently to provide control in the root zone yet not move into groundwater. Persistence in soil should be for an agriculturally effective yet environmentally safe period. Experimental approach and design are critical to achieving targets for expense, persistence and soil mobility. For example, the plant material should be inexpensively produced if not widely available. Bioassay-guided fractionation of compounds from known nematode-antagonistic plants may lead to the identification of compounds more interesting than those obtained by inferential deduction about the chemical nature of the phytochemical. Purification schemes should generally not focus on lipophilic compounds because of their poor ability to move in soil. The ideal bioassay organism should be a phytoparasitic nematode, not a microbivorous species which ideally would be unaffected. High minimally effective concentrations are not usually appropriate for future greenhouse or field experimentation, except in unusual circumstances.