Australia’s first case of glyphosate-resistant tall fleabane (<i>Conyza sumatrensis</i>) and alternative herbicide options for its control

Abstract Tall fleabane is emerging as a problematic weed species in the eastern cropping region of Australia. Recently, growers indicated poor control tall to field rate glyphosate fallow fields. Pot studies were conducted an open at Gatton farm University Queensland, Australia, confirm level resistance putative glyphosate-resistant (GR) population and evaluate performance alternative postemergence herbicides GR fleabane. Compared with glyphosate-susceptible (GS) population, was 4-fold 3.5-fold greater based on plant survival biomass, respectively. The target-site mechanism not present because both GS populations had same gene sequence. There several effective for small (4-leaf stage) plants fleabane, but large (12- 14-leaf plants, sole application saflufenacil + trifludimoxazin or its mixtures glyphosate, glufosinate, paraquat best herbicide treatments. This first published report occurrence Growers need use integrated management strategies mitigate further spread fields well crops.