Evaluation of the in-furrow nematicide velum total for management of meloidogyne incognita in cotton
Roper, Richard J.
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Root-knot nematodes (Meloidogyne incognita) are the most destructive of the plant-parasitic nematodes in the High Plains. In this region, approximately 50% of irrigated fields are infested and yield losses of up to 25% have been reported. Prior to 2011, the granular nematicide aldicarb, was the most widely used chemical treatment; however, it is no longer commercially available for use. New chemical management options are necessary to reduce crop losses due to M. incognita. Velum® Total, the primary product being evaluated in this study, is a novel fungicide/nematicide, fluopyram, plus the insecticide, imidacloprid. Field experiments were conducted in 2015 and 2016 to evaluate combinations of in-furrow applications of Velum® Total, cultivars that vary in their response to M. incognita, and the seed treatment nematicide Aeris® in fields with varying levels of M. incognita. There were no negative effects from either in-furrow or seed treatment nematicides on stand establishment or early season plant growth. Differences in stand, plant height, yield, fiber quality parameters, loan value, and net returns above variable cost (NRAVC) were observed between cultivars. Yields were greatest for Stoneville 4946GLB2 and lowest for FiberMax 1900GLT at 1756 and 1628 kg/ha, respectively. Use of the seed treatment nematicide was of limited effectiveness and caused a decrease in NRAVC at two of the five locations. Overall, applications of Velum® Total increased lint yields under high nematode pressure conditions. The highest rate increased lint yields by 167 kg/ha and the moderate rate numerically increased yield by 109 kg/ha, over the control. NRAVC was numerically decreased $32 per hectare at the high rate compared to the moderate rate in the high nematode pressure location. This corresponds to the significant decrease at two other locations and another numerical decrease at a fourth location. All of which indicates that the moderate rate application was more profitable than the highest rate application. Results from these studies suggest that cultivar selection is the most effective means of managing root-knot nematodes in cotton. Velum® Total is a viable management option in fields severely infested with M. incognita.