- Agronomic: potatoes
- Crop Production: varieties and cultivars, Soil testing
- Education and Training: decision support system
- Farm Business Management: disease managment decisions
- Pest Management: economic threshold
- Soil Management: soil microbiology, plant parasitic nematodes
Northern root-knot nematode (Meloidogyne hapla) is a significant soilborne pathogen of vegetables and potatoes in the Northeastern United States. Frequently, decisions regarding pesticide application for control of M. hapla and other plant-parasitic nematodes are routine and prophylactic in nature, often resulting in unnecessary applications, increasing the cost of production and having potential for off-site deleterious effects on the environment. Methods for traditional nematode enumeration in soil pre-plant (a measurement fundamental in determining when protective pesticide applications are needed) is often a time consuming and difficult process. This therefore limits the ability of growers to make time-sensitive decisions concerning prophylactic pesticide application. This project will develop new methods for assessment of plant-parasitic nematode populations using the M. hapla/potato pathosystem as a model system. These methods will be tested for accuracy and precision compared to standard manual extraction and counting for prediction of plant damage. The approach will utilize extraction of DNA from soil, a technique that shows promise in being significantly faster and more precise in species delineation than the traditional enumeration techniques. The project will incorporate information on edaphic factors, relating crop damage at harvest to quantification of DNA in soil prior to planting. The model developed will serve as a framework to build upon for assessing risk of a range of soilborne pathogens. Outreach activities will include providing on-farm risk probability consultations based upon findings of the research for growers participating in the study, presentation of results at grower meetings and scientific conferences, and development of agricultural extension materials.
Project objectives from proposal:
The objective of this multi-year project is to develop new a quantitative risk algorithm for Meloidogyne hapla that will predict tuber damage at harvest based upon initial pathogen population densities prior to planting and other edaphic factors such as soil type. The specific objectives are to:
(1) Develop and test a quantitative PCR (qPCR) procedure for quantifying inoculum of M. hapla across a range of soil types. To differentiate between M. hapla and other nematode species within soil samples species-specific primers based upon 16D10, an effector gene present within root knot nematode species, will be utilized.
(2) Assess the utility of the qPCR technique in establishing the relationship between soilborne pathogen DNA levels and tuber damage, supporting the development of new decision theory applications for monocyclic soilborne diseases.
(3) Test the relationship between M. hapla DNA and tuber damage by intensively sampling three commercial potato fields within New York State. This will further refine the risk algorithms developed and assess their utility under field conditions.
(4) Present the conceptual framework developed here for reducing pesticide usage through soil testing before planting developed in this study to New York growers though appropriate forums, including Cornell Cooperative Extension meetings, the NY Potato Advisory Group assemblies, and American Phytopathological Society Northeast Division conferences.