Efficacy and residue field trials of different copper rates on soft fruits

Abstract: In 2009, efficacy and residue field trials using different copper rates and formulationswere carried out in Trentino region (North-eastern Italy). In a blackberry and a red currantorchard, the following treatments were applied: three copper rates (99, 62 and 37g/hl of metalliccopper) of a commercial product containing copper sulphate, one formulation based on copperoxychloride (76g/hl of metallic copper) and a foliar fertilizer containing copper (15g/hl ofmetallic copper). Untreated plots were used as control. Copper residues on ripe fruits wereanalysed. Incidence of downy mildew (Peronospora sparsa) and anthracnose (Drepanopezizaribis) was evaluated for blackberry and red currant, respectively. Five applications of thedifferent copper treatments were made on red currant during the growing season. Analysis ofcopper residues on berries showed the overcoming of the MRL for the treatments with the highercopper concentration (99, 76, 62g/hl of metallic copper) while only the treatments with 37g/hland 15g/hl remained below the limit of 5mg/kg. On blackberry, seven applications were sprayedand the copper residues resulted below the MRL of 5mg/kg in all the treatments. In 2009, bothanthracnose and downy mildew showed generally a low rate of incidence, nevertheless all thecopper treatments significantly reduced the disease development compared to the untreated plots.No clear differences resulted between treatments with high and low copper rates and evenstrategies with reduced copper doses were effective to control the target pathogens.