Performing Department
(N/A)
Non Technical Summary
Plant parasitic nematodes are among the most important pests of crops in the United States. The USDA's Committee on National Needs and Priorities in Nematology estimated the value of plant damage by nematodes in the U.S. at $7-9 billion annually. Chemical control of nematodes has proven to be effective; however most nematicides have toxicological or environmental concerns and many are under regulatory pressure. The goal of this research is the development of novel, safe and effective nematicidal agents for use against plant-parasitic nematodes. An Active Mixture with specificity and activity against plant parasitic nematodes has been selected from a new class of safer chemistry. Formulation technology will be used to optimize bioavailability of the compound in soil achieving at least a five-fold improvement in potency. Performance in soil and spectrum of activity will be characterized and this information will be used to design a field evaluation program for Phase II
in key crops such as tomato, potato, tobacco, cotton, soybean, and turf. Positive results in Phase II will lead to the rapid commercialization of a new nematicide for U.S. growers.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
We have used the Caenorhabditis elegans genome sequence together with parasitic nematode expressed sequence tags (ESTs) and proprietary bioinformatics to identify genes that are essential in nematodes but are absent in mammals. Using a specific gene product as a target, we have identified a class of inhibitory compounds with good in vitro activity against several plant parasitic nematodes and with a favorable preliminary toxicology profile. Potted plant tests using Meloidogyne incognita on tomato have confirmed the potential of these compounds for use as agricultural nematicides. The Phase I research will utilize formulation technology to optimize the compounds performance in soil by improving their bioavailability and stability. The utility of the compounds for the specific needs of U.S. growers will be determined by characterizing their soil performance and spectrum of activity across multiple crops and nematode species. The specific objectives of this Phase I
proposal are (1) to develop a formulation that optimizes bioavailability and potency of the Active Mixture in soil, and (2) to determine the spectrum of activity of the best formulations on key species of plant-parasitic nematodes. We expect to develop a formulation that is active at 10 ppm or less, with demonstrable activity across a spectrum of plant-parasitic nematodes.
Project Methods
The compounds under investigation are in general lipophilic and have poor water solubility, limiting distribution and bioavailability in the soil. These and other performance characteristics may be significantly improved by the design of an emulsifiable formulation that is optimized for several characteristics. A series of surfactants and solvents will be altered in a controlled fashion for evaluation of positive impact on efficacy. Using a column-flush assay system, candidate formulations will be tested for increased efficacy against Meloidogyne incognita J2 larvae. A wide variety of formulations can be screened efficiently with this method. Confirmation and further characterization of promising formulations will be done in the greenhouse on potted tomato plants in sand infested with Meloidogyne incognita. Soil persistence and efficacy will also be determined in a potted root knot assay utilizing sand or sand containing 10% microbially active soil. Fenamiphos will be
used as the benchmark for soil longevity. Experiments to demonstrate the utility of specific formulations will be undertaken, using parasitic nematodes representing sedentary endoparasites (Heterodera glycines), migratory endoparasites (Pratylenchus scribneri), ectoparasites (Belonolaimus longicaudatus), and foliar nematodes (Aphelencoides spp.). Potted plant tests will be carried out on soybean, corn, turf and ornamentals, respectively. This research represent s the next stages of a rational approach to research and development of what may become the first new class of commercializable nematicidal reagents in more than twenty years.