Results of a chemical weed control trial in an oil olive orchard

Results of a chemical weed control trial in ten years old oil olive orchard (cv Nociara), ocated at Francavilla Fontana (Brindisi) in southern Italy are reported. The aim of the trial was to test the effectiveness of some herbicide treatments. Thesis compared were: a) pre-emergence distribution of azafenidin (an active ingredient that isn't yet registered in Italy) at different doses (200-240 and 480 g/ha of a.i.) and by one or two treatments; b) glyphosate (720 g/ha of a.i.) applied in post-emergence, alone and mixed with azafenidin (200 g/ha of a.i.); c) oxyflurfen (600 g/ha of a.i.) in a single pre-emergence application; c) tilled control; d) weedy control. Azafenidin showed a high and lasting level of efficacy, at all the doses, applied by only one treatment also, in the control of Anthemis arvensis L., Capsella bursapastoris (L.) Medicus., Conyza canadensis (L.) Cronq., Diplotaxis erucoides (L.) DC., Lolium spp., Poa spp., and Sonchus oleraceus L., but wasn't effective against Stellaria media L.; regarding the last species, the best result was obtained using oxyfluorfen that showed the same activity of azafenidin, applied alone or mixed to glyphosate. All herbicide treatments tested gave statistically no different crop yield than tilled control, but higher than weedy control, and showed a perfect selectivity.