Plant-parasitic nematodes are ubiquitous pests and serve as a major constraint to agricultural production across the North Central Region (NCR). The NCR includes the major U.S. production areas of corn, soybeans, and small grains. The NCR is also home to major production sites for several vegetable crops (e.g. sugar beets, cucurbits, potatoes). Plant-parasitic nematodes cause yield loss in all of these production systems. The long-term goal of our committee is the effective and economic control of plant-parasitic nematodes in the NCR.

Stakeholders (growers, crop consultants, breeders, agrochemical companies) require unbiased data regarding the management and biology of regionally important plant-parasitic nematodes. The soybean cyst nematode (SCN), Heterodera glycines, is the most damaging pathogen of soybean in the U.S. resulting in annual yield losses greater than $100 billion (Wrather and Koenning, 2006). Plant-parasitic nematodes on corn cause an estimated annual 5% yield loss (Society of Nematologists Crop Loss Assessment Committee, 1987). Economically significant yield losses caused by plant-parasitic nematodes on other regionally important field and vegetable crops are also well documented (Koenning et al., 1999). This project will answer fundamental and applied questions to address yield loss caused by plant-parasitic nematodes.

Numerous species of plant-parasitic nematodes are found throughout the NCR. However, there is substantial variability across the region in both the biology of individual nematode populations and edaphic factors affecting nematode populations. For example, the ability of SCN to reproduce on soybeans with a common source of resistance has changed over time and varies substantially across regions (Niblack et al., 2008). There is a critical need to coordinate research that will lead to improved plant-parasitic nematode control strategies that reach beyond the borders of individual states. Through our coordinated research activities, we can effectively dissect such variability in order to develop regional recommendations for managing plant-parasitic nematodes. Without such coordination, we will miss opportunities for synchronizing experimental design and for meaningful data comparisons across the NCR. This would, ultimately, reduce scientific progress and result in a stagnation of development of new plant-parasitic nematode control strategies. 

All proposed objectives utilize standard nematology techniques. The participants in this technical committee represent the primary nematology expertise from each participating NCR state and are, therefore, technically capable of completing all proposed research. Previous accomplishments from committee members include the standardization of nematode extraction techniques, the assessment of nematode resistance in commercial cultivars, assessment of nematode-protectant seed treatments, and the determination of risk thresholds for plant-parasitic nematodes on corn (MacGuidwin and Bender, 2012; Tylka et al., 2011). 

Because nematodes do not recognize state borders, data regarding the biology and control of these pests are most effectively collected through collaborative multistate research. For example, SCN is distributed throughout the NCR (Tylka and Marett, 2014); however SCN shows significant geographical variability in its ability to overcome host resistance (Niblack et al., 2008). A coordinated multistate effort is essential to develop novel plant-parasitic nematode control strategies that surpass individual site-specific considerations. While local conditions remain fundamentally important for the control of plant-parasitic nematodes, the integration of research strategies among nematologists and plant pathologists who work with nematode pests in the NCR are indispensable for rapid progress in the field. Furthermore, each NCRA member institution employs, on average, only 1.25 faculty nematologists. Multistate research is therefore essential for collaborative research in nematology. 

This project will lead to an increase in environmentally sustainable crop production by reducing yield loss caused by plant-parasitic nematodes. Based on 2012 crop production data (USDA Economic Research Service), a conservative estimate of 1% yield loss due to plant-parasitic nematodes translates into approximately $950 million in crop production loss for the NCR due to plant-parasitic nematodes. By combining applied and fundamental research with outreach activities, our project will improve the near- and long-term outlook for managing plant-parasitic nematodes.