1 March 2003 Common waterhemp (Amaranthus rudis) resistance to protoporphyrinogen oxidase-inhibiting herbicides
Douglas E. Shoup, Kassim Al-Khatib, Dallas E. Peterson
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Resistance to protoporphyrinogen oxidase (protox)-inhibiting herbicides was identified in a population of common waterhemp that had been treated with acifluorfen for several years. The protox-resistant biotype of common waterhemp was approximately 34, 82, 8, and 4 times more resistant than a susceptible common waterhemp biotype to acifluorfen, lactofen, fomesafen, and sulfentrazone, respectively. The resistant biotype also showed a high level of resistance to acetolactate synthase–inhibiting herbicides thifensulfuron and imazethapyr but not to glyphosate or paraquat. An organophosphate insecticide was applied with acifluorfen or lactofen to determine if metabolism could be the mechanism of resistance. No differences were observed between resistant plants treated with an organophosphate plus a protox-inhibiting herbicide and plants treated with a protox-inhibiting herbicide alone.

Nomenclature: Acifluorfen-methyl; lactofen; fomesafen; sulfentrazone; thifensulfuron-methyl; imazethapyr; glyphosate; paraquat; malathion; diazinon; common waterhemp, Amaranthus rudis Sauer AMATA.

Douglas E. Shoup, Kassim Al-Khatib, and Dallas E. Peterson "Common waterhemp (Amaranthus rudis) resistance to protoporphyrinogen oxidase-inhibiting herbicides," Weed Science 51(2), 145-150, (1 March 2003). https://doi.org/10.1614/0043-1745(2003)051[0145:CWARRT]2.0.CO;2
Received: 28 May 2002; Accepted: 9 July 2002; Published: 1 March 2003
ALS-inhibiting herbicides
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