Efficacy of fungicides against downy mildew of basil (Peronospora belbahrii) in Italy.

Sweet basil (Ocimum basilicum) is in Italy an economically important herb crop cultivated both in greenhouse and in field for fresh and mainly processed (pesto sauce) consumption. Downy mildew (Peronospora belbahrii) (Belbahri et al, 2005; Thines et al., 2009) is the major threat of this crop and it needs many fungicide applications. Over many years, metalaxyl-M was the most utilized active ingredient (a.i.) even if during the last years efficacy reductions were pointed out probably due to pathogen resistance issues (own data not yet published). Mandipropamid, azoxystrobin and fluopicolide+propamocarb a.i.s are also authorized but, because of the risk of resistance development, the availability of other products, possibly with different MoA, should be useful. The aim of this study was to evaluate the activity against P. belbahrii of some fungicides authorized in Italy on other herb crops but not on basil as dimethomorph, fosetyl-Al, amisulbrom and cyazofamid..............................