Effect of environmental conditions on fluopyram applied in-furrow on cotton nematodes

Fluopyram is a nematicide for use as an at-plant, in-furrow on cotton (among other crops) in the United States. Trials (33 total) were conducted in cotton fields with and without fluopyram applied at-plant, in-furrow in Meloidogyne incognita and Rotylenchulus reniformis infested fields. Root galling caused by M. incognita was reduced on average by 24% with fluopyram. The amount of rain for the first rain after planting did affect fluopyram activity, with 1, 2, and 3 cm rain predicted to reduce root galling by 15, 26, and 39%, respectively. On average, cotton lint yield in M. incognita tests was 7% higher with fluopyram (1,270 kg lint/ha) compared to no nematicide (1,185 kg lint/ha). Fluopyram did not significantly affect R. reniformis density or cotton lint yield in R. reniformis tests. Lint yield increased as the number of days until the first rain increased, and fluopyram-treated plots yielded more than no nematicide as days until the first rain increased. Lint yield decreased in R. reniformis fields as average air temperature increased (for the first 14 days), but the warmer the temperature, the bigger the difference between fluopyram (higher yields) than no nematicide (lower yields). There is strong evidence, even in a water-limited environment like west Texas, that significant early rains will improve fluopyram reduction of M. incognita galling and increase yield. The impact of fluopyram with R. reniformis is not as clear and trended opposite for beneficial environmental conditions compared to M. incognita.