Preemergence Herbicide Control of Eclipta alba in Container-grown Plants

Abstract

Preemergence herbicides were evaluated for control of yerba-de-tago [ Eclipta alba (L.) Hasskarl] and for phytotoxicity to four container-grown landscape species. Herbicides providing excellent control (less than one weed/pot) were chlorimuron at 0.035 and 0.07 kg·ha -1 , chlorimuron + metribuzin at 0.075 + 0.485 kg·ha -1 , and oryzalin at 4.5 and 9.0 kg·ha -1 . Injury within 30 days after treatment occurred with applications of oxyfluorfen, lactofen, and fomesafen at the × 1 and × 2 rates on Ilex vomitoria Ait. ‘Nana’ (dwarf yaupon), Rhododendron satsuki ‘Pink Gumpo’ (‘Pink Gumpo’ azalea), R. obtusum (Lindl.) Planch. ‘Coral Bells’ (‘Coral Bells’ azalea), and Liriope muscari L. ‘Big Blue’ (lily turf). Injury symptoms were not present after 60 days, except with applications of lactofen at 0.44 kg·ha -1 and fomesafen at 1.1 kg·ha -1 . All other herbicides were safe on the four ornamental species. Chemical names used: 2-chloro- N -(2-ethyl-6-methylphenyl)- N -(2-methoxy-1-methylethyl)acetamide (metolachlor); N , N -diethyl-2-(l-naphthaIenyloxy)propanamide (napropamide); 3-[2,4-dich-loro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3 H) -one (oxadiazon); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); N -(l-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); 6-chloro- N,N- diethyl-1,3,5-triazine-2,4-diamine (simazine); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate (bifenox); 2-chloro- N -(2,6-diethylphenyl)- N -(methoxymethyl)acetamide (alachlor); 2-[[[[4-chloro-6-methoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoic acid (chlorimuron); 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4 H )-one (metribuzin); (±)-2-ethoxy-l-methyl-2-oxoethyl 5-[2-chloro-4-(trifluoromethyl)phenoxyl]-2-nitrobenzoate (lactofen); and 5-[2-chloro-4-(trifluoromethyl)phenoxyl]- N -(methysulfonyl)-2-nitrobenzamide (fomesafen).