Control of Globodera spp. Using Brassica juncea Seed Meal and Seed Meal Extract

The eradication program for the potato cyst nematode (PCN), , in the Northwest of the United States revolves around the use of soil fumigation. Alternative, integrated strategies are needed to continue to battle this invasive nematode. Laboratory, greenhouse, and field experiments were conducted with and another cyst nematode found in the United States, , to evaluate the efficacy of a new formulated seed meal extract, as well as a traditional seed meal, as alternate eradication strategies. This is the first report on the efficacy of seed meal extract against plant-parasitic nematodes. Rates of seed meal greater than 2.2 t/ha and 4.5 t/ha for and , respectively, were required for egg hatch suppression, as determined by a potato root diffusate (PRD) bioassay. Reproduction of on potato after exposure to seed meal at a rate of 2.2 t/ha was also significantly reduced. In the field, 8.9 t/ha seed meal almost eliminated egg hatch of . Rates needed for spp. suppression were greatly reduced when using the seed meal extract. When compared side-by-side, half as much seed meal extract, 1.1 t/ha, was required to suppress egg hatch to the same extent as seed meal. Exposure of to seed meal extract at 4.5 t/ha reduced egg hatch by 90% compared with a nonamended control. The ability to reduce the amount of material being applied to soil by using an extract has the potential for integration into a eradication program.