Effect of treating cotton seeds on the population dynamics of Pratylenchus brachyurus under water stress conditions

The aim of this study was to evaluate the efficacy of seed treatment on the control of Pratylenchus brachyurus and on cotton plant development parameters under two water regimes. Seeds of the cotton cultivar FiberMax 966 were treated with products containing imidacloprid + thiodicarb, pyraclostrobin + thiophanate-methyl + fipronil, abamectin + azoxystrobin + mefenoxam + fludioxonil + thiamethoxam at varying doses. The plants were subjected to two water regimes (absence and presence of water stress), maintaining 30 and 60% field capacity 15 days after nematode inoculation. At 60 days after inoculation, the aerial part and root fresh mass were evaluated, together with total nematodes (soil + root). The results obtained show that all parameters were influenced by seed treatment in the presence and absence of water stress. Treatment with imidacloprid + thiodicarb resulted in greater aerial part fresh mass. For root fresh mass, all chemistry treatment improved root development, except abamectin + azoxystrobin + mefenoxam + fludioxonil + thiamethoxam, under both water regimes. The treatment containing pyraclostrobin + thiophanate-methyl + fipronil improved control of P. brachyurus in the absence of water stress. The results for treatments containing imidacloprid + thiodicarb, pyraclostrobina + thiophanate-methyl + fipronil, abamectin + azoxystrobin + mefenoxam + fludioxonil + thiamethoxam showed no difference in the control of nematodes in relation to water stress.