Response of Ragweed Parthenium (<i>Parthenium hysterophorus</i>) to Saflufenacil and Glyphosate

Abstract

Field and greenhouse studies were conducted in Belle Glade, FL, in 2010 and 2011 to evaluate saflufenacil and glyphosate efficacy on POST burndown of ragweed parthenium. Log-logistic models were used to determine the herbicide dose required to produce 90% control (ED 90 ). The ED 90 for rosette ragweed parthenium control in the greenhouse was saflufenacil at 8.0 g ai ha −1 at 14 d after treatment. The rate required to cause 90% growth reduction of rosette ragweed parthenium at 14 d after treatment was 8.9 g ha −1 of saflufenacil. The probability of rosette ragweed parthenium survival decreased with increasing rates of saflufenacil. The ED 90 value for bolted ragweed parthenium control in the field was 5.7 g ha −1 of saflufenacil at 21 d after treatment. Ragweed parthenium had no response to glyphosate either in the field or in the greenhouse studies. This demonstrates that saflufenacil can be used as a POST burndown of ragweed parthenium populations that have no response to glyphosate.