Effects of fluensulfone combined with soil fumigation on root-knot nematodes and fruit yield of drip-irrigated fresh-market tomatoes

After the phase-out of methyl bromide (MeBr) and the constant challenges of root-knot nematodes (RKNs, Meloidogyne spp.), the need to evaluate the efficacy of additional alternatives in tomato (Solanum lycopersicum L.) production is vital. Fluensulfone (Nimitz, ADAMA Agricultural Solutions Ltd., Raleigh, NC) is a true, contact nematicide developed to target RKNs. Among available chemical soil fumigants, Pic-Clor 60 [1,3-dichloropropene plus chloropicrin (40:60, w/w)] has been identified as one of the main alternatives to MeBr; however, nematode management in sandy soils with drip irrigation has been unsatisfactory. During the fall of 2014 and the spring of 2016, two replicated field experiments were conducted in Myakka City, FL with the objective of evaluating the efficacy of pre-plant drip-injected fluensulfone at 1.96 and 2.80 kg a.i.·ha−1 combined with pre-plant fumigated Pic-Clor 60 at 280 kg ha−1 on plant vigor, RKN soil population density, root galling index, and fruit yield of fresh-market tomatoes. All treatments showed uniform plant growth during both seasons. In 2014 and 2016, at final harvest, Pic-Clor 60 combined with fluensulfone at 1.96 and 2.80 kg a.i.·ha−1 decreased RKN densities compared to Pic-Clor 60 alone by 96 and 85% and 81 and 94%, respectively. Similarly, during 2014 and 2016, at mid-season and final harvest, less root galling was observed with Pic-Clor 60 combined with both fluensulfone rates than with Pic-Clor 60 alone. However, the effect of the combination of fluensulfone and Pic-Clor 60 on tomato yield was significant only at the third harvest in 2014 when RKN infestation was high. Fluensulfone combined with Pic-Clor 60 could be a viable alternative for managing RKNs in fresh-market tomato production in sandy soils using drip irrigation and in fields with high RKN infestation.