Meta-analysis of the field efficacy of seed- and soil-applied nematicides on Meloidogyne incognita and Rotylenchulus reniformis across the U.S. Cotton Belt

Authors: FASKE, TRAVIS - University Of Arkansas; KANDEL, YUBA - Iowa State University; ALLEN, TOM - Mississippi State University; GRABAU, ZANE - University Of Florida; KEMERAIT, ROBERT - University Of Georgia; LAWRENCE, GARY - Mississippi State University; LAWRENCE, KATHY - Auburn University; Mehl, Hillary; OVERSTREET, CHARLES - Louisiana State University; THIESSEN, LINDSEY - USDA National Plant Disease Recovery System; WHEELER, TERRY - Texas A&M University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2022
Publication Date: 1/3/2022
Citation: Faske, T.R., Kandel, Y., Allen, T.W., Grabau, Z.J., Kemerait, R.C., Lawrence, G.W., Lawrence, K.S., Mehl, H.L., Overstreet, C., Thiessen, L.D., Wheeler, T. 2022. Meta-analysis of the field efficacy of seed- and soil-applied nematicides on Meloidogyne incognita and Rotylenchulus reniformis across the U.S. Cotton Belt. Plant Disease. https://doi.org/10.1094/PDIS-07-21-1529-RE.
DOI: https://doi.org/10.1094/PDIS-07-21-1529-RE

Interpretive Summary: Root knot and reniform nematodes cause significant damage to cotton across the United States Cotton Belt. A multi-year, multi-location study was conducted across ten states to evaluate the effectiveness of different combinations of seed and soil applied nematicides for nematode control and cotton yield protection. Results were variable across location-years, but based on a meta-analysis, nematicides protected cotton yield in both root knot and reniform nematode infested fields. Treatments that included an in-furrow soil application of nematicide resulted in greater yield protection than treatments with only a seed applied nematicide. Though nematicides were effective for protecting cotton yield, they provided little suppression of nematode populations or root galling based on mid-season assessments. Results indicate that soil applied nematicides with or without a seed applied nematicide protect cotton yield potential, but additional management tactics are needed for long-term suppression of plant parasitic nematode populations in cotton fields.

Technical Abstract: Meta-analysis was used to compare the root and yield protection by two seed- and two soil-applied nematicides against Meloidogyne incognita and Rotylenchulus reniformis across three years and several trial locations in the United States Cotton Belt. Nematicides consisted of thiodicarb and fluopyram treated seed, in-furrow treatments consisting of fluopyram and aldicarb, and combinations of seed- and soil-applied fluopyram. The nematicides had a significant impact on cotton yield with an average yield response (¯D) of 176 and 197 kg/h relative to the nontreated control in both M. incognita and R. reniformis fields, respectively. However, because of significant variation, six moderator variables were used. In M. incognita fields, only application methods and nematicide treatments had a significant effect on the yield response. Of the application methods, nematicides applied in-furrow or with a seed-applied nematicide resulted in greater yield protection than seed-applied nematicides. Relative to thiodicarb, greater lint yield protection was provided by, aldicarb, soil applied fluopyram at >131 g ai/ha, and seed-applied + soil-applied fluopyram at 184 g ai/ha. In R. reniformis fields, no moderator variable provided any further explanation of the variation in yield response by nematicides. The nematicides provided little suppression of mid-season nematode reproduction or percent root system galled, and moderator variables did not provide any further explanation of variation in nematode suppression by nematicides. The nematicides provided limited nematode suppression; however, they were effective at protecting cotton yield potential in M. incognita and R. reniformis infested fields across the U. S. Cotton Belt.