Plant-parasitic nematodes significantly reduce the yield and quality of a wide range of crops, world-wide. Although recently quantified descriptions of these losses are difficult to obtain, average yield losses to nematode parasitism in the world’s major crops has been estimated to average 10-14% annually (Sasser and Freckman 1987). Annual crop losses in the US have been estimated to range from minimal for some commodities in some regions to an approximate maximum of 15% in others (Koenning et al, 1999).

The research in this proposal addresses important agricultural crop management issues as identified by the REE Advisory Board. In the Report on Agriculture Research Needs of Commodity Crops, the REE Advisory Board states that sustainable, efficient production of these staples (including cotton, soybean, and peanut) is critical to the US food supply and economy, and that “productive efficiency” must be a top priority in order to meet the demands of a growing population in the US and the world. They further list as top priorities, nematode resistance in cotton and improved varieties and disease resistance in peanut. Many farmers have relied on fumigant and non-fumigant pesticides to control plant-parasitic nematodes, but most of the non-fumigant nematicides are no longer available, and application of most soil fumigants now involves significant additional application restrictions and requirements. If the research in this proposal is not conducted, growers will experience greater production costs and yield losses. Nematode-resistant crops can lower production costs by reducing nematicide applications, while at the same time improve yield. Reduction in nematicide use will also reduce risks of environmental contamination and potential adverse effects on public health.

Host resistance to nematodes and other plant pests and pathogens is often cited as the preferred method of pest management (Cook and Starr, 2006), but some parasitic nematodes are able to adapt quickly to resistant cultivars and overcome the resistance (Vuong et al., 2013; Jones et al., 2013), and incorporating nematode resistance into superior genetic backgrounds for yield and quality attributes can be difficult (Starr et al., 2002). Nematode-resistant germplasm has been deployed in various crop plants (Concibido et al., 2004; Brucker et al., 2005; Kim et al., 2011; Starr et al., 2002), but with the narrow genetic basis for this resistance, new sources of host resistance are urgently needed. Nematode resistance is also almost always limited to a single nematode species, and is even sometimes limited to one or more specific “host races”. Crop production in the South frequently involves fields infested with multiple economically important plant-parasitic nematode biotypes that can adapt to nematode management practices, including crop rotations and host resistance (Starr et al., 2002).

For these reasons, resistance should be integrated into nematode management systems that include other control tactics in order to successfully manage the entire community of plant parasitic nematodes in commercial fields. These other tactics could include cropping systems (crop rotation and/or use of cover crops) and nematode management agents (NMA), which can include synthetic pesticides as well as biocontrol agents. Crop rotation, cover crops and soil amendments have been increasingly studied for their ability to suppress nematode population densities (Lu, et al., 2005), and considerable research is also being conducted on biofumigation and other methods to produce compounds that reduce preplant nematode populations (Zasada et al, 2010). Compounds applied to control other soilborne pathogens have been found, more recently, to also possess significant and useful nematicidal activity (Faske and Hurd, 2014). There have also been significant advances in the detection, identification, and use of biological agents that suppress nematodes (Timper, 2011). However, there has been very little research on integrating these other practices, particularly cultural and biological practices, with host-plant resistance. Thus, there is a need to evaluate the combined use of host resistance with cover crops, commercially available biological control agents, and other new NMAs, to control plant-parasitic nematodes.

Through this proposed regional project, there will be on-going scientist to scientist integration of research and outreach to accelerate progress. There are common crops that are vulnerable across states with programs that are locally specific; by sharing information on a timely basis what is learned at one location can have a significant effect on programs in other locations. The proposed project provides the formal relationship to facilitate multistate cooperative efforts with the annual meeting providing the incentive.