Response of an acetolactate synthase (ALS)-resistant biotype of Amaranthus rudis to selected ALS-inhibiting and alternative herbicides |
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| Authors: | C L SPRAGUE E W STOLLFR L M WAX |
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| Institution: | Department of Crop Sciences, University of Illinois, USDA-Agricultural Research Service, 1102 South Goodwin Avenue, Urbana IL 61801, USA |
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| Abstract: | An Amaranthus rudis Saner (common water-hemp) biotype from a field treated for two consecutive years with a mixture of chlorimuron and metribuzin was tested in greenhouse and laboratory studies to assess resistance and cross-resistance to four acetolactale synthase (ALS)-inhibiting herbicides. The biotype demonstrated >1920-fold resistance at the whole plant level, and >850-fold resistance at the ALS enzyme to chlorimuron, compared with a susceptible biotype. This chlorimuron-resistant biotype was also cross-resistant to primisuifu-ron, haiosulfuron and imazethapyr. In greenhouse studies, atrazine alone or in combination with ALS-inhibiting herbicides provided excellent control of the resistant biotype of A. rudis . Combinations of dicamba and ALS-inhibitors also provided adequate control. Additionally, premixtures of flumetsulam and metolachlor and of dicamba and atrazine furnished excellent control of this chlorimuron-resistant A. rudis biotype. |
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