Uniform Root Layer Application at Optimal Timing Can Effectively Improve Root-Knot Nematode Disease Control in Rui Yam

Root-knot nematode disease seriously threatens the production of Rui yams, making it important to explore effective management strategies, including the optimal time for disease control and efficient application techniques. In this study, we monitored the dynamics of a root-knot nematode J2 population in the soil using field sampling; moreover, we investigated the dynamics of root-knot nematode disease using a field sampling and visual in situ device based on identifying species of root-knot nematodes in Rui yams. Additionally, experiments pertaining to optimal application time and techniques were conducted in Ruichang and Nanchang. This is the first study to propose that chemical control should be optimally timed, with one application administered at the time of yam seedling flush, and another given approximately 60 days later. Applications of a 41.7% fluopyram suspension (1426 g.a.i./hm 2 ) and a 30% fosthiazate microencapsulated suspension (2925 g.a.i./hm 2 ) achieved disease control effects of 81.56–83.15% and 75.95–78.42%, respectively. Additionally, the comparative analysis demonstrated that using uniform root layer application technology at the optimal time produces a control effect exceeding 80%, which is significantly higher than conventional techniques such as drip irrigation and root irrigation. These results provide theoretical and technical support for the efficient control of root-knot nematode disease in Rui yams.