Situation and management of Avena sterilis ssp ludoviciana and Phalaris paradoxa resistant to ACCase inhibitors in Italy

All enquiries made to Syngenta about poor control of Avena sterilis ssp ludoviciana and Phalaris paradoxa were monitored over three years. More than 100 seed samples were collected from the affected fields and tested with one DIM and two FOP herbicides. All seed samples came from fields cultivated with durum wheat in central and southern Italy. Several populations of A. sterilis ssp ludoviciana and P. paradoxa proved to be resistant to one or more ACCase inhibitor herbicides. Two fields where the resistance situation was particularly serious were chosen for field experiments. Three years of experiments testing the efficacy of chemical and agronomic means for controlling resistant A. sterilis and P. paradoxa are presented. The emergence dynamics of the two resistant species was also determined in the same fields. For both species the situation appears to be evolving slowly. No single chemical or agronomic treatment solved the problem of resistant populations. False seedbed preparation and some alternative herbicides proved to be useful in controlling resistant populations. Integrated weed management appears to be the best solution.