Field experiments were conducted at the Tidewater Agric. Exp. Station, Suffolk,VAin 1988 and to evaluate imazethapyr [(±J-2-[4,5-dihydro-4-methyl-4-( 1-methylethyl)-5-oxo-1fi-imidazol-2-yl]-5-ethyl-3-pyridine-carboxylic acid]for broadleaf weed control in peanuts (Arachis hypogaea L.). Imazethapyr was applied preplant-incorporated (PPI), preemergence (PRE), at ground-cracking (GC), and postemergence (POT) at rates of 0.036, 0.071, or 0.105 kg ai ha'. Several sequential imazathapyr systems were also included. The standard of pendimethalin (Nethylpropyl)-3, 4-dimethyl-2,6-dinitrobenzenamine) PPI, metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide) PRE, and acifluorfen (5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid) plus bentazon (3-(1-methyethyl)-(lfi)-2,1,3-benzothiadiazin-4(3fi)-one 2, 2-dioxide) POT was included for comparative purposes. Imazethapyr applied either PPI or PRE at 0.071 or 0.105 kg ha' provided >90% spurred anoda (Anoda cristata (L.) Sehlecht.), control and >96% prickly sida (Sida spinosa L.), control. Eclipta (Eclipta prostrata L.) control was 95% when imazathapyr was applied PRE at 0.105 kg ha'. Greater than 90% annual morningglory (Ipomoea spp.) control was only achieved with imazethapyr applied PPI or PRE at 0.105kg ha'. The standard provided complete control of eclipta,and 51%,92%, and 94% control of spurred anoda (Anoda cristata (L.) Schlecht.), pricklysida (Sidaspinosa L.), and annual morningglories, respectively. Several imazethapyr systems yielded equivalent to the standard. Averaged across all rates, imazathapyr applied PPI 'For, Asst. Prof

Field experiments were conducted in 1988 and 1989 to evaluate imazethapyr for weed control in peanuts. Imazethapyr was applied PRE or POST at 3, 5, or 7 weeks after crop emergence (WAE) at 0.071 kg ai ha–1. Imazethapyr applied PRE controlled common lambsquarters 85%, prickly sida 92%, and a mixture of entireleaf, ivyleaf, pitted, and tall morningglory species 77%. Morningglory control was at least 91% with imazethapyr plus metolachlor PRE followed by imazethapyr plus 2,4–DB or imazethapyr plus acifluorfen at 3, 5, or 7 WAE. Yields from systems that included metolachlor plus imazethapyr PRE followed by imazethapyr plus acifluorfen, imazethapyr plus 2,4–DB, or acifluorfen plus 2,4–DB at 3 WAE were greater than yields from the handweeded check. All systems with imazethapyr plus metolachlor PRE followed by any POST treatment except imazethapyr plus acifluorfen 7 WAE provided net returns equivalent to the herbicide standard of metolachlor PRE and acifluorfen and bentazon plus 2,4–DB 3 WAE. All systems except imazethapyr PRE provided greater net returns than the handweeded weed–free check.

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