Belonolaimus longicaudatus management using metam potassium and fluensulfone in potato.

Belonolaimus longicaudatus (sting nematode) is an important pest in Florida potato production and is managed primarily by fumigation using 1,3-dichloropropene (1,3-D). Other effective nematicides are needed for more flexibility in managing this pest. The objective of this study was to evaluate fluensulfone, metam potassium, and mixtures of the two products, relative to 1,3-D and untreated control, for efficacy at managing sting nematode, and for non-target effects on free-living nematodes in potato. To test this objective, a small-plot field experiment was conducted in northeast Florida in 2020 and repeated in 2021. Metam potassium fumigation (390 kg a.i./treated ha)-with or without fluensulfone-managed sting nematode soil abundances but was phytotoxic to potato. Strategies that mitigate metam potassium phytotoxicity, such as reduced application rates, are needed before efficacy of metam potassium in this system can be determined. As a preplant soil spray, fluensulfone alone (403 g a.i./treated ha) did not manage sting nematode abundances and had an inconsistent effect on yield. Fumigation with 1,3-D (88.3 kg a.i./treated ha) was the only treatment that consistently managed sting nematode and increased potato yield. Nematicides did not consistently affect free-living nematodes.

Fluensulfone and 1,3-dichloroprene for plant-parasitic nematode management in potato production.

Florida produces 35% of the spring potato (Solanum tuberosum) crop in the USA, but plant-parasitic nematodes suppress yield in the region. The stubby-root nematodes, Paratrichodorus (Nanidorus) spp. and Trichodorus spp., vectors for corky ringspot disease, and sting nematode (Belonolaimus longicaudatus) are among the most damaging nematodes in Florida potato production. Nematicide application is an important component of nematode management in this system, but relatively few nematicides are currently available. Therefore, pre-plant applications of fluensulfone nematicide at various rates (3, 4, 6, and 8 l/ha) and the commercial standard fumigant 1,3-dichloropropene (1,3-D) were tested for management of plant-parasitic nematodes in three field trials from 2016 to 2018. Both fluensulfone, at all rates, and 1,3-D consistently decreased sting nematode abundance relative to the untreated control at harvest. Neither fluensulfone nor 1,3-D affected stubby-root nematode abundances at harvest. Efficacy of fluensulfone and 1,3-D for lesion nematode (Pratylenchus sp.) management varied by year. In 2016 and 2018, fluensulfone at most rates and 1,3-D increased marketable potato yield relative to the untreated control with increases by 49 to 66% and 33 to 55% in 2016 and 2018, respectively. In 2017, fluensulfone at lower rates (3, 4, and 6 l/ha) increased marketable potato yield relative to the untreated control by 41 to 61%, but fluensulfone at 8 l/ha and 1,3-D had similar yields to the untreated control. Results suggest that nematicidal activity of fluensulfone and 1,3-D varies by target nematode with both products effective against sting nematode, ineffective against stubby-root nematodes, and inconsistent against lesion nematode. In conclusion, fluensulfone and 1,3-D are effective options for sting nematode management in Florida potato production.Florida produces 35% of the spring potato (Solanum tuberosum) crop in the USA, but plant-parasitic nematodes suppress yield in the region. The stubby-root nematodes, Paratrichodorus (Nanidorus) spp. and Trichodorus spp., vectors for corky ringspot disease, and sting nematode (Belonolaimus longicaudatus) are among the most damaging nematodes in Florida potato production. Nematicide application is an important component of nematode management in this system, but relatively few nematicides are currently available. Therefore, pre-plant applications of fluensulfone nematicide at various rates (3, 4, 6, and 8 l/ha) and the commercial standard fumigant 1,3-dichloropropene (1,3-D) were tested for management of plant-parasitic nematodes in three field trials from 2016 to 2018. Both fluensulfone, at all rates, and 1,3-D consistently decreased sting nematode abundance relative to the untreated control at harvest. Neither fluensulfone nor 1,3-D affected stubby-root nematode abundances at harvest. Efficacy of fluensulfone and 1,3-D for lesion nematode (Pratylenchus sp.) management varied by year. In 2016 and 2018, fluensulfone at most rates and 1,3-D increased marketable potato yield relative to the untreated control with increases by 49 to 66% and 33 to 55% in 2016 and 2018, respectively. In 2017, fluensulfone at lower rates (3, 4, and 6 l/ha) increased marketable potato yield relative to the untreated control by 41 to 61%, but fluensulfone at 8 l/ha and 1,3-D had similar yields to the untreated control. Results suggest that nematicidal activity of fluensulfone and 1,3-D varies by target nematode with both products effective against sting nematode, ineffective against stubby-root nematodes, and inconsistent against lesion nematode. In conclusion, fluensulfone and 1,3-D are effective options for sting nematode management in Florida potato production.