Resistance to very-long-chain fatty-acid (VLCFA)-inhibiting herbicides in multiple field-selected rigid ryegrass (Lolium rigidum) populations. Issue 3 (11th March 2019)

• Record Type: Journal Article
• Authors: Brunton, David J.; Boutsalis, Peter; Gill, Gurjeet; Preston, Christopher
• Is Part Of: Weed science. Volume 67:Issue 3(2019)
• Page Start: 267
• Page End: 272
• Publication Date: 2019-03-11
• Subjects: Franck E. Dayan, Colorado State University; Chloroacetamides, -- cross-resistance, -- herbicide resistance, -- multiple resistance, -- PRE herbicides, -- sulfonylisoxazoline, -- thiocarbamates; 632.505
• DOI: 10.1017/wsc.2018.93
• Languages: English
• ISSNs: 0043-1745

Abstract

Abstract: Five populations of rigid ryegrass ( Lolium rigidum Gaudin) from fields across cropping regions in southern Australia were suspected of having resistance to thiocarbamates, chloroacetamides, and sulfonylisoxazoline herbicides. Resistant (R) populations 375-14, 198-15, 16.2, EP162, RAC1, and A18 and two susceptible (S) populations (SLR4 and VLR1) were included in a dose–response study. All suspected R populations expressed resistance to one or all herbicides (thiocarbamates, chloroacetamides, and pyroxasulfone). Population 198-15 exhibited the highest LD50 to triallate (44.7-fold), prosulfocarb (45.7-fold), S -metolachlor (31.5-fold), and metazachlor (27.2-fold) compared with the S populations. Populations 198-15 and 375-14 were also resistant to pyroxasulfone (13.5- and 14.9-fold) compared with the S populations, as was population EP162. This study documents the first case of field-evolved resistance to thiocarbamate, chloroacetamide, and sulfonylisoxazoline herbicides in L. rigidum .