Publication Date


Advisor(s) - Committee Chair

James Worthington, Ray Johnson, W.C. Normand

Degree Program

Department of Agriculture

Degree Type

Master of Science


Johnsongrass (Sorghum halepense) competition in soybeans (Glycine max) has adverse effects on soybean yields. Profitable soybean production in Kentucky and the Southeastern United States has depended upon good, cost effective johnsongrass control. Several herbicides have been developed to control johnsongrass in soybeans. Four of these recently developed compounds were imazaquin (2-[4,5-dihydro-4-methy1-4- (1-methyl-ethyl)-5-oxo-1H-imidazo1-2-y1]-3-quino1inecarboxy1ic acid), imazethapyr (+/-)-2-C4,5-dihydro-4-methy1-4-(1-methy. lethyl)-5-oxo-IH-imidazol-2-y1)-5-ethy1-3-pyridinecarboxylic acid, quizalofop 2-[4-[(6-chloro-2-quinoxalinyl) oxylphenoxyjpropaonic acid,ethyl ester, and analog of quizalofop (DPX Y6202-31).

Field experiments were conducted in 1986 to evaluate (a) the effectiveness of imazaquin and imazethapyr preplant incorporated, postemergence, or in combination with pendimethalin [N-(1-ethylpropy1)-3,4-dimethy1-2.6-dinitrobenzenamine], and (b) herbicide antagonism with fluazifop[butyl(R)-2-(4-[(5- trifluoromethy 1 ) - 2-pyridinl] oxy] phenoxy] propanoate], quizalofop, sethoxydim [2-[1-(ethoxyimino)butyl] -5-(2- (rthylthio)propy1]-3-hydroxy-2-cyclohexen-l-one, fenoxaprop [(+/-)-2-[4-((6-chloro-2-benzoxa-zoly) oxy]phenoxy]propanoic acid], and DPX-Y6202-31, in combination with imazaquin, bentazon [3-(1-methylethyl)-(ih)-2,1,3, benzothiadiazin- 4(3h)-one 2,2-dioxide], acifluorfen [5-[2-chloro-4(trifluoromethyl) phenoxy]-2-nitrobenzoic acid], and chlorimuron [3-(3,4-dichloropheny1)-1-methoxy-1-methylurea and Ethyl 2--[[[[(4-chloro-6-methoxy-pyrimidin-2-yl)amino)-carbonyl] amino]sulfonyl]binzoate], for johnsongrass control in soybeans.

Imazaquin was applied preplant incorporated, tankmixed with pendimethalin and imazethapyr. Imazethapyr was applied preplant incorporated and postemergence with surfactant at equal rates.

DPX-Y6202-31 was applied postemergence at four different rates, and in tankmix combinations with chlorimuron, acifluorfen, bentazon, and imazaquin, with surfactant or crop oil contrate. Quizalofop was applied postemergence at tour use rates.


Agriculture | Life Sciences | Plant Sciences | Weed Science