Evaluation of fumigant and non-fumigant nematicides for management of Rotylenchulus reniformis on sweetpotato.

Reniform nematode (Rotylenchulus reniformis) is a major pest of sweetpotato in many production regions in Southern United States. Applying soil fumigants and non-fumigant nematicides are the primary management strategies available to growers. This study compared the relative efficacy of nematicides (1,3-dichloropropene, fluopyram, oxamyl, fluazaindolizine, aldicarb, Majestene, and fluensulfone) for management of reniform nematode on sweetpotato. Fumigating soil with 1,3-dichloropropene consistently reduced soil population densities of reniform nematode at the time of planting in both trial years (31 - 36% reduction relative to the untreated control); however, the duration of suppression varied greatly by growing season. A similar trend was observed with fluopyram (56 - 67% reduction) and aldicarb (63 - 65% reduction), which provided season-long suppression of reniform nematode population development in 2021 but had no impact in 2022. In 2021, nematicide application had no impact on yield; however, in 2022, oxamyl and aldicarb increased the yield of U.S.#1 grade sweetpotato. Overall, soil fumigation with 1,3-dichloropropene and in-furrow application of fluopyram and aldicarb provided the most consistent suppression of reniform nematode on sweetpotato.