Susceptibility of Arkansas Palmer amaranth accessions to common herbicide sites of action

• DOI: 10.1017/wet.2020.56
• Publication Date: 2020-05-26T07:18:47Z
• Authors: Fidel González-To...; Jason K. Norsworthy; Leonard B. Piveta; Vijay K. Varanasi; Tom Barber; Chad Brabham
• Keywords: Glufosinate; Dicamba; Trifluralin; Metolachlor; Protoporphyrinogen oxidase

Abstract Palmer amaranth is one of the most difficult-to-control weeds in row crop systems and has evolved resistance to several herbicide sites action (SOAs). A late-season weed-escape survey had been conducted earlier determine distribution protoporphyrinogen oxidase–inhibitor resistant Amaranth Arkansas. The objective this study was evaluate susceptibility Arkansas accessions commonly used SOAs. SOAs evaluated were group 2 + 9, 3, 4, 5, 10, 14, 15, 27, representative from each imazethapyr glyphosate (79 860 g ha −1 ), trifluralin (1,120 dicamba (280 560 atrazine (560 glufosinate (594 fomesafen (395 S -metolachlor (1,064 tembotrione (92 respectively. mortality varied among across Averaged accessions, rates, by treatment order lowest highest, as follows: (16%), (51%), at 280 (76%), (82%), (85%), (87%), (96%), (99.5%). This provides evidence that with low imazethapyr, fomesafen, are widespread throughout Of remaining SOAs, sensitive; however, within SOA, except glufosinate, control some less than expected suspected.