Weed population dynamics and unpredictable weather make weed control extremely challenging on the Texas Southern High Plains. Experiments were conducted in 1990-1993 growing seasons to evaluate the efficacy of Staple (DPX-PE350) on annual broadleaf weeds in cotton and to evaluate rotational crop response to Staple. Staple at 0.016 to 0.125 lbs ai/A was applied preplant incorporated (PPI), preemergence (PRE), and postemergence (POST) in cotton. Control of pigweed (Amaranthus sp.), devilsclaw (Proboscidea louisianica (Mill.) Thellung), venice mallow (Hibiscus trionum L.), lanceleaf sage (Salvia reflexa Hornem.), and morningglory (Ipomoea sp.) was evaluated throughout each growing season. In other studies, winter wheat, corn, soybean, and sorghum were planted in the growing seasons following PPI, PRE, and POST (early-, mid-, late-, and rescue-POST treatments) applications of Staple to cotton at 0.094 and 0.19 lb ai/A. Crop injury was evaluated one- and two-years following applications.

All applications (PPI, PRE, POST) of Staple at 0.063 lbs ai/A effectively controlled pigweed (>80%), but only moderately controlled devilsclaw (50-60%). Staple at 0.063 lbs ai/A controlled lanceleaf sage and venice mallow more effectively when applied PRE compared to POST, whereas control of puncturevine and annual morningglory species by Staple at 0.063 lbs ai/A was more effective when applied POST compared to PRE.

Staple at 0.19 lbs ai/A caused visual injury to winter wheat, soybean, corn, and sorghum planted the growing season following cotton. Staple at 0.094 lbs ai/A did not injure winter wheat and only the POST application slightly injured soybean. No injury to winter wheat and soybean was observed two years after application, but slight injury was observed on corn and sorghum. Carryover of POST treatments was greatest when applied mid- and late-season, while early and rescue POST treatments caused less crop injury.

Staple offers effective and selective control of many broadleaf weeds with the versatility of being applied PPI, PRE, and POST in cotton. Carryover injury to crops grown in rotation with cotton may occur. Future studies will examine the influence of irrigation, tillage, and application time and method (band versus broadcast) on Staple carryover.