Evaluation of Imazaquin for Weed Control in Flue-Cured Tobacco (Nicotiana tabacum)

Abstract

Imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} was evaluated in the field for weed control in flue-cured tobacco (Nicotiana tabacumL.) during 1983 and 1984. The 75 DG formulation of imazaquin was used at 0.28 and 0.42 kg ai/ha. Methods of application were: preplant incorporated, over the top immediately after transplanting, postbed incorporated, and early postemergence. Imazaquin controlled 90%, or better, of common lambsquarters (Chenopodium albumL. # CHEAL), common ragweed (Ambrosia artemisiifoliaL. # AMBEL), redroot pigweed (Amaranthus retroflexusL. # AMARE), spiny amaranth (Amaranthus spinosusL. # AMASP), ivyleaf morningglory [Ipomoea hederacea(L.) Jacq. # IPOHE], sicklepod (Cassia obtusifoliaL. # CASOB), and prickly sida (Sida spinosaL. # SIDSP) with all application methods except early postemergence. It controlled 80 to 89% of large crabgrass (Digitaria sanguinalisL. # DIGSA) by the soil-applied methods. Postemergence applications of imazaquin controlled common ragweed, pigweed spp., ivyleaf morningglory, prickly sida, and sicklepod. Imazaquin was less effective postemergence on lambsquarters and large crabgrass. Tobacco tolerated use of imazaquin by all methods of application except preplant incorporation.