A field trial was carried out at Jundiaí, São Paulo State (Brazil), during the growing seasons of 2006/2007 and 2007/2008, in a 'Niagara Rosada' grapevine trained on a Y shaped trellis with and without plastic overhead cover aiming to evaluate the effects on: microclimate, disease incidence, yield and cluster quality. The spraying schedules used were: Standard (weekly sprays) and Control (no sprays). It was verified that the use of plastic overhead cover had no influence on maximum and minimum air temperature, and relative humidity. Yield values for the grapevines grown under plastic cover (3.52 to 6.99 kg plant-1) were higher than the Control treatment at open sky condition (1.81 to 2.34 kg plant-1). The evaluations of incidence of anthracnose, downy mildew, leaf spot and bunch rot allowed to verify that the Control treatment under plastic cover did not show disease incidence up to harvest, even though no fungicide was used. The Y shaped trellis grapevines grown under plastic overhead cover improved cluster quality and decreased disease incidence.
trellis; plastic cover; anthracnose; downy mildew; leaf spot; bunch rot; microclimate
