Management of Meloidogyne incognita on cucumber with a new nonfumigant nematicide fluopimomide.

Cucumber is an economically important vegetable crop in China. Southern root-knot nematode (Meloidogyne incognita) is a significant obstacle in cucumber production, causing severe root damage and yield losses. Moreover, resistance development to fosthiazate, and poor mobility of abamectin have led to failure to control this nematode. It is of great interest to growers and the vegetable industry to explore novel nonfumigant nematicides that can provide adequate control in an environmentally friendly manner. Fluopimomide, a new chemical having a similar structure to fluopyram, was shown to exhibit toxic effects on fungi and nematodes. The efficacy of fluopimomide to reduce infection of M. incognita in cucumber was evaluated under greenhouse and field conditions. In the greenhouse, fluopimomide at all test rates resulted in a 22.5-39.6% and 31.3%-55.0% reduction in the population density of M. incognita in the soil at 30 and 60 days after treatment (DAT), respectively, compared with the non-treated control. Fluopimomide at 500 and 750 g ha-1 reduced (p < 0.05) root galling, meanwhile increasing plant height compared to the non-treated control at 30 and 60 DAT. In the field trials, fluopimomide at 500 and 750 g ha-1 decreased the population density of M. incognita and root galling 57.2-69.9% compared to the untreated control, while enhancing cucumber yield in two consecutive years. Furthermore, fluopimomide at 500 g ha-1 combined with fosthiazate was the most effective treatment showing a synergistic effect on reducing population densities of M. incognita, which was significantly greater than either fluopimomide or fosthiazate by themselves. In summary, fluopimomide has considerable potential for managing M. incognita on cucumber.