TY - JOUR
T1 - Confirmation and control of glyphosate-resistant common waterhemp (Amaranthus rudis) in Nebraska
AU - Sarangi, Debalin
AU - Sandell, Lowell D.
AU - Knezevic, Stevan Z.
AU - Aulakh, Jatinder S.
AU - Lindquist, John L.
AU - Irmak, Suat
AU - Jhala, Amit J.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - Glyphosate-resistant common waterhemp is a difficult-to-control annual broadleaf weed that has become a serious management challenge for growers in Nebraska and other states in the United States. The objectives of this study were to confirm glyphosate-resistant common waterhemp in Nebraska by quantifying level of resistance in a dose-response study, and to determine the sensitivity and efficacy of POST soybean herbicides for controlling suspected glyphosate-resistant common waterhemp biotypes. Seeds of suspected glyphosate-resistant common waterhemp biotypes were collected from seven eastern Nebraska counties. Greenhouse dose-response experiments were conducted to evaluate the response of common waterhemp biotypes to nine rates of glyphosate (0 to 16×). Common waterhemp biotypes were 3- to 39-fold resistant to glyphosate depending on the biotype being investigated and the susceptible biotype used for comparison. Results of the POST soybean herbicides efficacy experiment suggested that glyphosate-resistant biotypes, except a biotype from Pawnee County, had reduced sensitivity to acetolactate synthase (ALS)-inhibiting herbicides (chlorimuron-ethyl, imazamox, imazaquin, imazethapyr, and thifensulfuron-methyl). Glufosinate and protoporphyrinogen oxidase (PPO)-inhibiting herbicides (acifluorfen, fluthiacet-methyl, fomesafen, and lactofen) provided ≥ 80% control of glyphosate-resistant common waterhemp at 21 d after treatment (DAT). This study confirmed the first occurrence of glyphosate-resistant common waterhemp in Nebraska, and also revealed reduced sensitivity to ALS-inhibiting herbicides in most of the biotypes tested in this study. Nomenclature: Acifluorfen; chlorimuron-ethyl; fluthiacet-methyl; fomesafen; glufosinate; glyphosate; imazamox; imazaquin; imazethapyr; lactofen; thifensulfuron-methyl; common waterhemp, Amaranthus rudis Sauer; soybean, Glycine max (L.) Merr.
AB - Glyphosate-resistant common waterhemp is a difficult-to-control annual broadleaf weed that has become a serious management challenge for growers in Nebraska and other states in the United States. The objectives of this study were to confirm glyphosate-resistant common waterhemp in Nebraska by quantifying level of resistance in a dose-response study, and to determine the sensitivity and efficacy of POST soybean herbicides for controlling suspected glyphosate-resistant common waterhemp biotypes. Seeds of suspected glyphosate-resistant common waterhemp biotypes were collected from seven eastern Nebraska counties. Greenhouse dose-response experiments were conducted to evaluate the response of common waterhemp biotypes to nine rates of glyphosate (0 to 16×). Common waterhemp biotypes were 3- to 39-fold resistant to glyphosate depending on the biotype being investigated and the susceptible biotype used for comparison. Results of the POST soybean herbicides efficacy experiment suggested that glyphosate-resistant biotypes, except a biotype from Pawnee County, had reduced sensitivity to acetolactate synthase (ALS)-inhibiting herbicides (chlorimuron-ethyl, imazamox, imazaquin, imazethapyr, and thifensulfuron-methyl). Glufosinate and protoporphyrinogen oxidase (PPO)-inhibiting herbicides (acifluorfen, fluthiacet-methyl, fomesafen, and lactofen) provided ≥ 80% control of glyphosate-resistant common waterhemp at 21 d after treatment (DAT). This study confirmed the first occurrence of glyphosate-resistant common waterhemp in Nebraska, and also revealed reduced sensitivity to ALS-inhibiting herbicides in most of the biotypes tested in this study. Nomenclature: Acifluorfen; chlorimuron-ethyl; fluthiacet-methyl; fomesafen; glufosinate; glyphosate; imazamox; imazaquin; imazethapyr; lactofen; thifensulfuron-methyl; common waterhemp, Amaranthus rudis Sauer; soybean, Glycine max (L.) Merr.
KW - Acetolactate synthase inhibitor
KW - glutamine synthetase inhibitor
KW - protoporphyrinogen oxidase inhibitor
KW - resistance management
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UR - http://www.scopus.com/inward/citedby.url?scp=84926011597&partnerID=8YFLogxK
U2 - 10.1614/WT-D-14-00090.1
DO - 10.1614/WT-D-14-00090.1
M3 - Article
AN - SCOPUS:84926011597
SN - 0890-037X
VL - 29
SP - 82
EP - 92
JO - Weed Technology
JF - Weed Technology
IS - 1
ER -