Glyphosate-resistant horseweed from Delaware

Abstract No-tillage corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production has been widely accepted in the mid-Atlantic region, favoring establishment of horseweed [Conyza canadensis (L.) Cronq.]. Within 3 yr of using only glyphosate for weed control in continuous glyphosate-resistant soybeans, glyphosate failed to control horseweed in some fields. Seedlings originating from seed of one population collected in Delaware were grown in the greenhouse and exhibited 8- to 13-fold glyphosate resistance compared with a susceptible population. There were no differences between the isopropylamine or diammonium salts of glyphosate. Nomenclature: Corn; Zea mays L.; horseweed; Conyza canadensis (L.) Cronq. ERICA; soybean; Glycine max (L.) Merr.; glyphosate.

[1]  Lim Jung Lee,et al.  A first report of glyphosate‐resistant goosegrass (Eleusine indica (L) Gaertn) in Malaysia , 2000 .

[2]  Z. Szigeti,et al.  Paraquat and atrazine co-resistance in Conyza canadensis (L.) Cronq , 1988 .

[3]  S. Weller,et al.  Differential Susceptibility of Field Bindweed (Convolvulus arvensis) Biotypes to Glyphosate , 1984, Weed Science.

[4]  Christopher Preston,et al.  Evolved resistance to glyphosate in rigid ryegrass (Lolium rigidum) in Australia , 1998, Weed Science.

[5]  Z. Szigeti,et al.  Photosynthetic Properties and Cross-Resistance to Some Urea Herbicides of Triazine-Resistant Conyza canadensis Cronq (L.) , 1987 .

[6]  D. Wyse,et al.  Recurrent selection for glyphosate tolerance in birdsfoot trefoil , 1991 .

[7]  R. Schmid,et al.  World Weeds: Natural Histories and Distribution , 1997 .

[8]  Patricia A. H. Williams,et al.  Resistance to glyphosate in Lolium rigidum , 1999 .

[9]  D. Johnston,et al.  HERBICIDE RESISTANCE IN THE GRAMINACEAE - A PLANT BREEDER'S VIEW , 1991 .

[10]  J. Pratley,et al.  Resistance to glyphosate in Lolium rigidum. II. Uptake, translocation, and metabolism , 1999, Weed Science.

[11]  S. Weller,et al.  Heritability of glyphosate susceptibility among biotypes of field bindweed , 1987 .

[12]  J. E. Jensen,et al.  Log-Logistic Analysis of Herbicide Dose-Response Relationships , 1995, Weed Technology.

[13]  J. Pratley,et al.  Resistance to glyphosate in Lolium rigidum. I. Bioevaluation , 1999, Weed Science.