Previous Cropping Sequence Affects Plant-Parasitic Nematodes and Yield of Peanut and Cotton More than Continuous Use of Fluopyram

Cropping sequence can have a major impact on diseases, pests, nutrient cycling, crop yield, and overall financial return at the farm level for crops that are grown on an annual basis. In some cases, implementing an effective rotation sequence can allow growers to avoid using nematicides to suppress plant-parasitic nematodes. Two cropping system trials were established with ten rotations each in 1997 and have been maintained through 2022. From 2013 through 2019, rotation sequences were both favorable and unfavorable for peanut (Arachis hypogaea L.) plant health. Peanut (2020), cotton (Gossypium hirsutum L.) (2021), peanut (2022), and corn (Zea mays L.) (2023) were planted in all plots to determine the residual effects of the previous cropping sequence. In 2020, 2021, and 2022, fluopyram at 0.25 kg ai/ha was applied in the seed furrow at planting in the same area of each plot to determine if the response of nematode populations and crop yield to this nematicide differed based on previous crop sequence. Differences in nematode populations in soil and yield of peanut (2020 and 2022) and cotton (2021) were observed when comparing crop rotation sequences regardless of fluopyram treatment. Increasing the number of years peanut was in the rotation or including soybean [Glycine max (L.) Merr.] rather than corn or cotton often resulted in higher populations of nematodes and a lower peanut yield. While fluopyram occasionally reduced nematode populations in soil and root injury from nematode feeding, the yield of peanut did not differ when comparing non-treated and fluopyram-treated peanut. When pooled over crop rotation sequence, peanut yield at Lewiston–Woodville was 5970 kg/ha vs. 6140 kg/ha for these respective treatments. At this location in 2021 and at Rocky Mount in 2019 and 2020, peanut yield for this comparison was 4710 vs. 4550, 5790 kg/ha vs. 6010 kg/ha, and 6060 kg/ha vs. 6120 kg/ha, respectively. These data indicate that previous crop sequences can influence crop yield more than the continuous use of fluopyram. Therefore, fluopyram is not recommended for application in the seed furrow at planting to suppress nematodes in cotton or peanut in North Carolina.