The 4lb/gal (4F) formulation of oxyfluorfen was significantly safer than the 2 lb/gal (2XL) formulation on broccoli when applied at the 2 or 3-leaf stages of growth. At 6 days after treatment of the first application at the cotyledon stage of the broccoli, significant injury to the broccoli ranged from 30 to 66% for all oxyfluorfen treatments. Crop stand reduction did not occur with either formulation. The 4F formulation at 0.25 lb AI/A gave nearly the same weed control as the 2XL formulation at 0.063 lb AI/A. The 4F formulation applied at the broccoli cotyledon stage of growth provided longer effective weed control for more than 3 weeks after applications. Later applications gave effective weed control for a period of time between 1 to 2 weeks.

Select (clethodim) and BAS-620 (BASF Corporation) at 0.1, 0.125, and 0.188 lb AI/A gave near complete control (99%) of watergrass at 8 days after treatment of the early application in watermelons and cantaloupes. Poast (sethoxydim) and Fusilade DX (fluazifop-p-butyl) offered nearly similar effective control of the watergrass with control ranging from 93 to 98%. Poast demonstrated a rate response with decreasing efficacy with decreasing rates of application. Fusilade and Poast at the high rate were comparable to Select and BAS-620 at the high rate. In lettuce, Select and BAS-620 performed similarly on large volunteer wheat with 97% control at about 3 weeks after treatment. Fusilade provided an acceptable level of control at 86% control. Poast did not provide any visible control of the volunteer wheat. Differences existed in the performance of the grass herbicides and optimal performance could be obtained with proper timing of application at effective rates and using effective adjuvants.

A field test was conducted to evaluate and determine the safety of halosulfuron on typical rotational crops such as lettuce, broccoli, spinach, onion, alfalfa, barley, field corn, and melons after an initial application on cantaloupes. Halosulfuron at 0.05 or 0.1 lb AI/A applied on cantaloupes did not detrimentally affect crop stand establishment, height, or whole plant fresh weights when alfalfa, barley, spinach, lettuce, onion, and broccoli were planted at approximately 4 to 5 MAT. Cantaloupes and field corn planted at 1 YAT were not affected in establishing a stand and in growing during the early season as height or vine lengths were measured. At 15 to 16 MAT, lettuce, onion, and broccoli were not affected in establishing a stand. Watermelon planted at 1 YAT exhibited slight stand reduction and crop injury with halosulfuron applied PREE. Alfalfa planted after PREE applications indicated slightly depressed height and yield compared to POST treatments and the untreated check. Spinach planted where POST applications were made on cantaloupes tended to show a slight reduction in fresh weight at 15 to 16 MAT. Halosulfuron does not appear to be a major deterrent to typical crop rotational schemes in the diverse desert agricultural systems.

Azafenidin (Milestone®, Dupont) and flumioxazin (Valor®, Valent)) caused cantaloupe injury that was very marginal between acceptable (<15%) and unacceptable (>15%). Flufenacet (Bayer), isoxaben (Gallery, DowAgroSciences), and thifensulfuron (Harmony®, Dupont) at the rates tested caused severe crop injury. Isoxaben provided very good weed control (>90%), azafenidin provided acceptable control of only lambsquarters at 88% and less than acceptable (85%) control of pigweeds, purslane, and grasses, and flumioxazin at the higher rate of 0.05 lb AI/A tended to offer slightly better weed control than the lower rate but overall it was marginally acceptable. Bensulide (Prefar®) combined with flumioxazin caused negligible crop phytotoxicity and better than 93% control for purslane, pigweeds, lambsquarters, and grasses. Combinations of herbicides offered slightly improved weed control compared to herbicides applied alone. Crop injury increased for combinations with dimethenamid (Outlook®, Frontier®, BASF) and s-metolachlor (Dual Magnum®, Syngenta).

Three rates of Stinger (Clopyralid) were evaluated for weed control, crop safety and soil persistence in broccoli. Efficacy tests indicated that 0.25 pt./A was ineffective in controlling volunteer alfalfa; while 0.5 pt produced marginal control and 1.0 pt. produced excellent control. No injury was noted at any rate. 140 days after treatment, injury was moderate to severe to alfalfa, moderate to tomatoes, cotton, carrots and lettuce and slight to onions.

Halosulfuron applied alone gave marginal to good control of common lambsquarters and common purslane, respectively, but did not provide control of the pigweeds. Acceptable control of 85% of the limited population of purple nutsedge was observed. Rimsulfuron applied alone gave good control of the pigweeds, lambsquarters, purslane, and marginal control of nutsedge. Weed control was effective until the late season evaluation at 9 WAT. The combination of halosulfuron and rimsulfuron gave similar results of the rimsulfuron applied alone, however, nutsedge control was not evaluated due to insufficient populations. Halosulfuron treated melons showed the least injury among all of the herbicide treatments applied alone. Rimsulfuron caused marginally unacceptable injury at 18% compared to flumetsulam, thifensulfuron, MKH-6561, and flufenacet which caused unacceptable injury ranging from 20 to 68%.

Sandea at 0.03 lb AI/A combined with rimsulfuron at 0.02 lb AI/A gave exceptionally good control of prostrate pigweed and lambsquarters at 98% and 96%, respectively, when applied postemergence (POST) in cantaloupes. Sandea applied POST in a tank-mix with increasing rates of rimsulfuron showed marginally acceptable to unacceptable crop injury. All POST applications of Sandea following preemergence (PREE) herbicides or applied alone provided 90% or better control of lambsquarters. Sandea and Strategy gave unacceptable control of pigweed and lambsquarters at 60-70% relative to the standard, Prefar. Sandea applied alone POST was less effective against pigweed than lambsquarters. A treatment of a PREE herbicide followed by Sandea was not as efficacious as the Sandea plus rimsulfuron tank-mix applied POST to control both pigweed and lambsquarters.

Three tests were conducted to compare delayed applications of Kerb applied by air with those applied through the sprinklers. Early (6-5-02) season and mid (10-20-02) applications made through the sprinklers were significantly more effective than those applied by air. The late season (11-17-02) application was made too early and the weed control was poor demonstrating the need for proper timing regardless of the application technique. It was concluded that chemigation can be an effective technique for making delayed applications of Kerb to lettuce in the low deserts.

Broccoli and red table beets emerged and established a stand in Sandea treated plots at 0.5 or 1.0 oz product/A. Table beets planted into the beds treated with Sandea did not exhibit significantly different rates of emergence and stand establishment relative to the untreated check. The broccoli that emerged and established a stand did not show any significant differences or numerical trends between the untreated check and the two Sandea treatments during any of the observation dates. Spinach, the third indicator crop, did not emerge adequately in the test site.

Callisto at 0.24 lb AI/A applied PREE gave a similar level of control of prostrate pigweed as did Dual Magnum, Outlook, and Prowl. POST applications of Callisto at 0.188 lb AI/A were equivalent to the higher rate of 0.24 lb AI/A. Callisto, Distinct, and Clarity provided excellent POST control of pigweed. Callisto applied POST was the same as PREE followed by POST sequentially. Aim provided marginally acceptable control of pigweed.