In 1987 a field study was conducted to evaluate several herbicide systems for ivyleaf morningglory (Ipomoea hederacea), entireleaf morningglory (Ipomoea hederacea var. integriuscula), and velvetleaf (Abutilon theophrasti) control in cotton and to evaluate the utilization of fluometuron and methazole postemergence on cotton during early stages of cotton development. Plots were established near Portageville, Missouri as a randomized complete block design with four replications. All herbicide treatments followed 0.75 lb ai/A trifluralin preplant incorporated (ppi) and 1.25 lb ai/A fluometuron preemergence (pre). Post-directed treatments were applied to 4 (PD4) and 7 (PD7) inch (in) cotton according to the herbicide label. Fluometuron + MSMA (1 + 2 lb ai/A), prometryn + MSMA (0.5 + 2 lb ai/A) and methazole (0.38 -lb ai/A) with and without MSMA (2 lb ai/A) were directed to 4 in cotton. Cyanazine (0.75 lb ai/A) and oxyfluorfen + MSMA (0.25 + 2.C lb ai/A) were post-directed to 7 in cotton. All post-directed treatments received 0.25% v/v surfactant. All treatments were applied with a hand held CO₂ backpack sprayer with a carrier rate of 187 1/ha.

All post-directed treatments resulted in greater than 90% control of morningglories at 8 WAP with the exception of probe (88%). Oxyfluorfen + MSMA and cyanazine, both applied PD7, resulted in 28 and 48% injury, respectively. In spite of crop injury caused by some treatments, there were no differences in seed cotton yields. Cyanazine (35-5) resulted in the lowest lint percent of all treatments.

Only the high rate of RE-40885 (1-5 lb ai/A) achieved excellent preemergence morningglory control. However, 74 and 79 percent control of morningglories was obtained with RE-40885 at .15 + .15 lb ai/A (pp'- + pre) and .25 + .25 lb ai/A (ppi + pre), respectively. Greater than 90% control was obtained with RE-40885 applied sequentially at 0.50 + .25 lb ai/Ac (pre + EPB). Lactofen resulted in excellent (95%) burndown of morningglories and velvetleaf early, however, control was only 79 and 81%, respectively, for morningglories and velvetleaf at 8 WAP due to weed regrowth.

Methazole applied early postemergence ((EP) 3 in cotton with 1 true leaf) and PD4 gave superior morningglory and velvetleaf control than methazole applied to cotton in the cotyledon stage. The most injury (30%) resulted from methazole applied EP. Methazole applied to cotton in the coty stage and EP resulted in, reduced cotton seed weight and percent, lint. Fluormeturon applied EP was more injurious to cotton than when applied to coty cotton or PE4.