Herbicide treatments of tank mixtures or sequential applications were applied at different growth stages and compared with standard treatments for control of barnyardgrass [Echinochloa crus-galli(L.) Beauv. ♯ ECHCM], bearded sprangletop [Leptochloa fascicularis(Lam.) Gray ♯ LEFFA], and aquatic weeds in rice (Oryza sativaL. ‘Starbonnet’). Some herbicides injured rice more than the propanil (3’,4’-dichloropropionanilide) or molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) standards, but injury for all treatments was inconsequential. Postemergence tank mixture treatments that controlled barnyardgrass (two- to four-leaf stages), bearded sprangletop (two-leaf to tillering stages), and aquatic weeds better than standard treatments were propanil plus butachlor [N-(butoxymethyl)-2-chloro-2’,6,-diethylacetanilide], oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] thiobencarb {S-[(4-chlorophenyl)methyl]diethylcarbamothioate}, or pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine].

Preplant incorporation of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] at 3.6 kg ai/ha, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 2.2 kg ai/ha, and tank mixtures of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} with either alachlor at 0.14 + 2.2 kg ai/ha or metolachlor at 0.14 + 1.1 kg ai/ha controlled >90% red rice (Oryza sativaL. # ORYSA) in soybeans [Glycine max(L.) Merr.]. Also, FMC-57020 [2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone] at 1.7 kg ai/ha applied preplant incorporated controlled > 80% of the red rice. DPX-Y6202 {2-[4-[(6-chloro-2-quinoxalinyl)oxy]-phenoxy]-propionic acid, ethyl ester} was the best and most consistent postemergence herbicide treatment for red rice control when applied once at 0.28 kg ai/ha or sequentially at 0.14 kg ai/ha each time. Haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy] phenoxy] propanoic acid} applied at 0.16 kg ai/ha followed by another application at 0.14 kg ai/ha gave excellent red rice control in 2 of 3 years. Soybeans were uninjured by the herbicide treatments and yield was higher from treated than untreated soybeans.

Diclofop [2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid] was evaluated to determine Italian ryegrass (Lolium multiflorumLam.) control and effect on yield of winter wheat (Triticum aestivumL.). Diclofop applied at 0.5, 0.75, 1.0, and 1.5 kg/ha postemergence provided excellent control of ryegrass and resulted in significant yield increases of winter wheat. Diclofop was most effective when applied at the two- to three-leaf stage of Italian ryegrass growth. Postemergence applications of diclofop plus bentazon [3-isopropyi-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] gave excellent control of ryegrass and significant increases in wheat yields.

Barnyardgrass and bearded sprangletop are severe weed pests in rice in the southern United States. These weeds are controlled with standard herbicide programs of propanil alone or propanil combined with pendimethalin or thiobencarb. However, new herbicides, such as fenoxaprop, may be effective alternatives for grass weed control in rice. Fenoxaprop at 0.17 kg ai/ha applied postemergence in programs with propanil, thiobencarb, or pendimethalin controlled barnyardgrass and bearded sprangletop in rice and performed as well as or better than standard treatments of propanil with thiobencarb or pendimethalin. Rice yielded well, and grain was of high quality.

Field experiments determined the potential interaction of insecticides and propanil [N-(3,4-dichlorophenyl) propanamide] in drill-seeded rice (Oryza sativaL. ‘Bond’). The carbamate insecticides carbaryl (1-naphthylmethylcarbamate) and methomyl {S-methylN-[(methylcarbamoyl) oxy] thioacetimidate} interacted more severely with propanil than the organophosphate methyl parathion [O,O-dimethylO-(p-nitrophenyl) phosphorothioate] in emulsifiable or encapsulated formulations. Carbaryl and methomyl injured rice vegetatively when applied from 7 days before to 4 days after propanil. Carbaryl was the only insecticide that interacted with propanil to reduce rice grain yield. Insecticides interacted adversely with propanil on rice grain yield when they were applied 2 days before propanil treatment. Insecticide interactions with propanil from most to least phytotoxic to rice plants for all times of application were: carbaryl > methomyl > emulsifiable methyl parathion > encapsulated methyl parathion.