Evaluating management programs utilizing fumigation and genetic resistance for control of southern root-knot nematode in a pepper-cucumber rotation

Root-knot nematodes (RKN; Meloidogyne spp.) are the most prevalent and damaging nematode taxa on solanaceous and cucurbit vegetable crops in the southeastern United States (U.S.). An RKN-resistant pepper hybrid was evaluated for its effects on root galling, RKN population density, and yield in a pepper-cucumber double crop system, relative to a susceptible hybrid and compared with factorial treatments of 1,3-dichloropropene (1,3-D) fumigation in Kinston, NC. Effects of these treatments were also evaluated on the subsequently planted cucumber. These results guided the selection of seven different nematicide and pepper hybrid combinations, as management programs, for a three-year study in Elm City, NC. Treatment effects on yield, root damage, and population densities of free-living and plant-parasitic nematode species were examined. In Kinston, both 1,3-D fumigation and the RKN-resistant hybrid significantly reduced root galling and RKN densities. Use of the RKN-resistant pepper hybrid was the only factor to significantly improve pepper and second crop cucumber yields (P<0.05). In Elm City, higher pepper and cucumber yields were observed in RKN management programs that included the RKN resistant pepper hybrid combined with fluopyram application, regardless of fumigation application. No significant difference in densities of free-living or plant parasitic nematode species were observed across management programs, though RKN densities trended lower when using an RKN resistant hybrid. These results highlight the potential for increasing yields and improving RKN management in pepper-cucumber rotations by using RKN-resistant pepper hybrids, combined with fluopyram application. Reducing dependence on 1,3-D fumigation improves both the economic and environmental sustainability of vegetable production.