Efficacy of Herbicide Combination on Burley and Dark-Air Cured Tobacco

摘要

The efficacy of herbicide combination on burley and dark air-cured tobacco Nictotiana tabacum were tested in field research plots in the summer of 2000 at Western Kentucky Universityu27s Agricultural Research and Education Complex. The randomized complete block design contained six treatments replicated three times in each of the two experiments (burley and dark air-cured tobacco). Transplants (cv. u27TN 97u27 and cv. u27KY 160u27) were established on June 2, 2000 in a conventionally tilled Pembroke silt loam soil with a pH of 6.5 and organic matter content of 12 g/kg. Herbicide treatments were applied on June 1, 2000 with a CO2 backpack sprayer. Six treatments were applied to both burley and dark air-cured plots. Sulfentrazone was applied alone and in combination with either clomazone, pendimethalin, or napropamide. A sulfentrazone + clomazone combination followed by sethoxydim, as well as a clomazone + pendimethalin tank mix were also evaluated. Weeds targeted for control were: Ipomoea hederacea L. (ivyleaf morningglory), Amaranthus hybridus L. (smooth pigweed), and Eleusine indica L. (goosegrass). Sulfentrazone alone provided u3e69% control of smooth pigweed and u3e89 % control of ivyleaf morningglory in burley and dark-air cured tobacco. At 21 days after treatment (DAT) the combinations of sulfentrazone/pendimethalin, sulfentrazone/clomazone/sethoxydim, and clomazone/pendimethalin gave better control of smooth pigweed in burley tobacco than did sulfentrazone/clomazone, but there were no differences between treatments at later evaluation dates. In dark-air cured tobacco, at 21 DAT sulfentrazone and the sulfentrazone/napropamide combination provided better control of smooth pigweed than did sulfentrazone/sethoxydim, but there were no differences between treatments at later evaluation dates. With respect to ivyleaf morningglory control, addition of herbicide combinations did not provide an advantage to sulfentrazone alone. Goosegrass control in dark-air cured tobacco was u3e 85% at all DAT, and control was u3e 45% in the burley plot. Control of goosegrass in both types of tobacco was u3e 94% with the triple combination of sulfentrazone/clomazone and sethoxydim at all evaluation dates, yet all combinations provided u3e86% goosegrass control at all evaluation dates. Addition of herbicides to sulfentrazone, (with the exception of napropamide) provided an advantage to goosegrass control in burley tobacco.