Response of Weedy and Commercial Okras (Abelmoschus esculentus) to Preemergence Herbicides

Abstract

The comparative susceptibility of weedy okra [Abelmoschus esculentus (L.) Moench.] and three commercial okra cultivars (′Dwarf Green Long Pod′, ‘Clemson Spineless', and ‘White Velvet′) to six preemergence herbicides was evaluated in the greenhouse. Okra can be controlled in cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] fields with appropriate preemergence herbicide use. Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one] completely controlled okra at 0.2 to 0.8 kg/ha. Fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] at 0.9 to 1.8 kg/ha and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile} at 1.2 to 2.4 kg/ha controlled okra, but at the 0.6 kg/ha rate cyanazine did not control wild okra and fluometuron at 0.45 kg/ha did not completely control any cultivar. Norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3 (2H)-pyridazinone] bleached the cotyledons and young leaves of okra, but gave 50% or less control even at 2.4 kg/ha. Both the weedy and commercial okras were completely resistant to trifluralin (α,α,α-trifluoro-2,6-dinitro -N,N-dipropyl-p-toluidine) and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] but higher rates of these herbicides affected okra growth.