Five field studies on sandy soils with ≤ 1% organic matter in south Texas showed that halosulfuron at 0.066 kg/ha preemergence (PRE) controlled ≥ 92% purple nutsedge and at 0.066 kg/ha postemergence (POST) controlled purple nutsedge 77 to 95%. Sulfentrazone at 0.11 to 0.28 kg/ha PRE or POST controlled purple nutsedge < 65% at one location but > 75% at two other locations. Poor control at the one location may have been due to a lack of early-season rainfall or irrigation. Potatoes were stunted 5 to 26% with halosulfuron PRE, whereas POST treatments caused 7 to 40% stunting. Sulfentrazone at 0.11 to 0.28 kg/ha applied PRE or POST caused 2 to 38% stunting. ‘Atlantic’ potato stunting with sulfentrazone POST at 0.14 to 0.28 kg/ha was ≥ 20%, whereas ‘Snowden’ and ‘1625’ potatoes were stunted ≤ 20%. Potato yields were reduced 65 and 39% with sulfentrazone and halosulfuron POST, respectively, at the high rates, but yield reductions occurred with all POST treatments on Atlantic potatoes 10- to 20-cm tall. Halosulfuron PRE at 0.033 kg/ha and sulfentrazone PRE at 0.14 kg/ha did not reduce yields; however, all other treatments of halosulfuron and sulfentrazone reduced potato yields.

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Field studies were conducted from 1995 through 1998 to evaluate citronmelon control with postemergence (POST) herbicides. Imazapic at any application timing and late postemergence (LPOST) applications of 2,4-DB were the only herbicides that provided >80% control of citronmelon late season. Other herbicides such as acifluorfen, imazethapyr, lactofen, and pyridate provided acceptable (>75%) early-season control of citronmelon, but control was inadequate at harvest.