Herbicide Resistant Weeds

Organic arsenical-resistant common cocklebur biotypes.

Haigler, W. E., B. J. Gossett, and J. R. Harris. 1986. Organic arsenical-resistant common cocklebur biotypes. Proceedings, Southern Weed Science Society, 39th annual meeting. : 105.

A Xanthium strumarium biotype resistant to organic arsenicals was found in 3 counties of the South Carolina coastal plains region in 1985. The biotype was resistant to post-em. treatments of bentazone, 2,4-DB, atrazine, fluometuron, acifluorfen, paraquat, glyphosate, chlorimuron and imazaquin. Control of the resistant (R-) biotype required 8-16 times more DSMA than the susceptible (S-) biotype. DSMA at 2.24 or 4.48 kg/ha only controlled the R-biotype at the 11 cm stage, whereas 1.12-4.48 kg controlled S-biotypes with a plant height of 11-125 cm. Under non-competitive field conditions the biotypes followed similar patterns of growth and development, but the R-biotype was taller than the S-biotype from 6 weeks after planting until maturity.