Integrated protection of table-grape from powdery mildew in Southern Italy

Abstract: Powdery mildew (Erysiphe necator Schw.) is one of the most severe diseases of grapevine wherever the crop is grown, especially under hot and dry climate like that occurring in the Mediterranean area. Two field trials were conducted on table-grape in Southern Italy in 2007 and 2008, to evaluate the effectiveness of different spray schedules based on the following fungicides: boscalid, either alone or in mixture with kresoxim-methyl; metrafenone; myclobutanil, either alone or in mixture with sulphur or meptyldinocap; penconazole; proquinazid; pyraclostrobin+metiram; quinoxyfen, either alone or in mixture with sulphur; sulphur; tebuconazole; trifloxystrobin. The climatic conditions during both the trials were particularly favourable to the pathogen, so that prevalence values of 97-100% of infected bunches in the untreated plots were reached at the end of both trials. Under such disease-conducive conditions, all the tested spray schedules always allowed a statistically significant reduction of disease incidence as compared to the untreated check. In particular, the best results were obtained when kresoxim-methyl+boscalid, pyraclostrobin+metiram, proquinazid or quinoxyfen had been applied during the periods of highest disease pressure.