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Title:Efficacy and Metabolism of Benazolin and Its Interactions With Acifluorfen, Bentazon, 2,4-Db, and Mcpa
Author(s):Whatley, Laura Lee Medlen
Department / Program:Agronomy
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Agronomy
Abstract:The purposes of this study were to determine the efficacy of using benazolin (4-chloro-2-oxobenzothiazolin-3-ylacetic acid), both alone and in combination with acifluorfen (sodium 5-{2-chloro-4-(trifluoromethyl)-phenoxy}-2-nitrobenzoate) bentazon {3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2 dioxide}, MCPA ({(4-chloro-o-toyly)oxy}acetic acid), or 2,4-DB {4-(2,4-dichlorophenoxy)butanoic acid} for postemergence broadleaf weed control in soybeans {Glycine max (L.) Merr.}; to compare benazolin activity to auxin activity; and to study benazolin metabolism in resistant/tolerant and susceptible plant species.
In two years of field observation, benazolin applied alone rarely killed broadleaf weeds. However, it did induce persistent growth malformations and phenoxy herbicide type injury in common cocklebur (Xanthium pensylvanicum Wallr.), jimsonweed (Datura stramonium L.), and velvetleaf (Abutilon theophrasti Medic.). Tank mixes of benazolin + acifluorfen or benazolin + bentazon generally suppressed common cocklebur and velvetleaf growth better than benazolin alone. Benazolin + X-77 surfactant or crop oil concentrate combinations increased velvetleaf injury. Jimsonweed was quite sensitive to all of the compounds. An ethyl ester benazolin formulation was slightly more active than a dimethyl amine salt formulation. In all cases, small weeds were suppressed more easily than large ones.
In greenhouse studies, weeds were ranked for susceptibility to benazolin. Jimsonweed and common cocklebur were quite sensitive to the compound. Benazolin produced fair to good suppression of smooth pigweed (Amaranthus hybridus L.), and fair suppression of Pennsylvania smartweed (Polygonum pensylvanicum L.) and ivyleaf morningglory {Ipomoea hederacea (L.) Jacquin}. However, velvetleaf exhibited only slight growth suppression due to benazolin. Further evaluations with those species indicated that benazolin + 2,4-DB or benazolin + bentazon provided better control than benazolin combinations including acifluorfen or MCPA.
Benazolin was found to function as an auxin in the pea straight growth bioassay. When compared to naturally occurring indole-3-acetic acid it was approximately 100 times less active.
Benazolin was applied to a leaf or leaflet of common cocklebur and soybean growth in solution culture. Treated plants were sectioned and harvested 12, 24, 48, and 96 h later. Unaltered benazolin was recovered from aerial soybean tissue 12 h and 24 h after treatment. However, in common cocklebur, unaltered benazolin was recovered only from a wash of the treated leaf.
Issue Date:1982
Description:204 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982.
Other Identifier(s):(UMI)AAI8218585
Date Available in IDEALS:2014-12-16
Date Deposited:1982

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