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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #62408
Title: RESISTANCE TO ARYLOXYPHENOXYPROPIONATE HERBICDES IN A LOLIUM MULTIFLORUM BIOTYPE FOUND IN FRANCE

Author
item GASQUEZ, J - INRA, FRANCE
item GIMENEZ-ESPINOSA, R - UNIV. OF CORDOBA, SPAIN
item Gronwald, John
item DE PRADO, R - UNIV. OF CORDOBA, SPAIN

Submitted to: International Symposium on Weed & Crop Resistance to Herbicides Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/5/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Poor control of a Lolium multiflorum biotype by graminicides has been observed for the past 4 to 5 years in a field in Normandy. Experiments conducted in the greenhouse with plants in the 3-4 leaf stage indicated that the resistant biotype exhibited 100% and 34% survival when treated with 5760 g/ha and 23040 g/ha diclofop, respectively. This biotype is also oresistant to fluazifop, clodinafop, and low levels of cycloxydim, but is not resistant to quizalofop, alloxydim or sethoxydim. The resistant biotype exhibited no cross-resistance to recommended field rates of atrazine, diuron, chlorotoluron, propyzamide, alachlor, metolachlor or benfluralin. The susceptibility of acetyl-CoA carboxylase (ACCase) activity to aryloxyphenoxypropionate and cyclohexanedione herbicides was measured in leaf extracts from resistant and susceptible biotypes. The I50 values (herbicide concentrations that inhibit enzyme activity by 50%) for diclofop, fluazifop, and haloxyfop were approximately 39, 89, and 19-fold greater, respectively, for the resistant biotype compared to the susceptible biotype. For the cyclohexanediones, clethodim, cycloxydim, and sethoxydim, the I50 values were approximately 3, 5, and 5-fold greater for the resistant biotype. The results suggest that resistance to the aryloxyphenoxypropionates in the Lolium biotype is due to the presence of a mutant, herbicide-resistant form of ACCase.