Glyphosate-resistant crops will be grown for the first time in Western Australia in 2009. A survey was conducted across 150,000 km2 of the southeastern part of the Western Australian grain belt in 2007 to determine whether glyphosate-resistant Conyza populations were present. Sixty-eight Conyza populations were collected from various fields and roadside locations. These populations were collected from areas where Conyza was known to exist. Populations were screened with glyphosate and all populations were found to be glyphosate-susceptible. While no glyphosate-resistant Conyza populations were found in the southeastern grain belt of Western Australia, it provides baseline data prior to the introduction of glyphosate-resistant crops in this region. It is important to monitor the efficacy of glyphosate as resistance becomes more prevalent in weeds of various cropping systems worldwide.
Nomenclature: Glyphosate; Conyza spp.
