Optimization of plant protection products treatments against Plasmopara viticola.

Plant protection in conventional farming, and even more so in organic farming, requires careful and prudent action agro-environmental monitoring and epidemic risk assessment. Often, however, the plant protection products are distributed in a non-targeted way, even when reduced incidence of pests do not require any treatment. In order to optimize the treatments against downy mildew, multi-annual field trials, both in conventional and organic vineyards, have been carried out. In all farms were considered 3 thesis: 1 untreated control thesis (Test), in order to follow the coarse of infection, 1 standard farm reference thesis (St), where the treatments were carried out according to the usual farm procedures and 1 experimental thesis (X). Guideline EPPO/OEPP PP 1/31 (3) have been carried out. We monitored different environmental parameters capable to influence Plasmopora viticola (Berk. and Curt.) Berl. and De Toni development. In fact by a network of RTUs (Remote Terminal Units) distributed all over the vineyards transmitting every 15 minutes via radio or via GPRS to a centralized Data Base 12 environmental parameters: time, data, precipitation, soil temperature, solar radiation, wind direction, wind speed, atmospheric relative humidity, atmospheric temperature, leaf wetness, soil humidity to cm 20 and soil humidity to cm 40. In different phenological growth stages we carried out careful disease assessments on leaves and bunches to evaluate the onset and development of P. viticola. We have studied the downy mildew infections through monitoring the environmental parameters, knowledge of P. viticola biological cycle, the evaluation of cultivar sensibility, the agricultural production method and the area characteristics, to try to optimize the anti- downy mildew treatments. The achieved results have underlined the possibility to obtain a satisfactory protection against P. viticola by correct placing of treatments. In experimental thesis (X) the number of treatments was generally lower than the number made on the thesis standard (ST), with efficacy comparable if not better. This result is most evident in conventional farms where surveillance is less accurate because is can also use plant protection products with a curative action. The trial showed the possibility of obtaining real cost containment management and a lower environmental impact associated with reduced fungicidal treatments.