Among the causes for weed control inefficacy, the worst one is resistance to herbicides. The objectives of this work were to evaluate an Eleusine indica biotype suspected of resistance to ACCase inhibitors and to investigate the occurrence of cross- resistance to several ACCase inhibitors. One biotype of Eleusine indica originated from Mato Grosso with suspected resistance to ACCase inhibitors was evaluated in a greenhouse in relation to its susceptibility to several products of the ariloxyphenoxypropionate and cyclohexanedione groups. Studies on dose response confirmed that the suspected biotype was 18 times more insensitive to sethoxydim than the susceptible biotype that had never been treated with herbicides. Cross-resistance was confirmed for fenoxaprop, cyhalofop, propaquizafop and butroxydim. No cross-resistance was observed with fluazifop, haloxyfop, quizalofop, and clethodim.
resistance; herbicides; weed; grass
