Photo-selective plastic nets in young peach orchards

The present work investigated photo-selective hail net (yellow, red and blue) effects on young nectarine trees (Prunus persica L.) in a typical production area in Northern Italy (Faenza, RA), compared with black net, the most used locally. The study was carried out during three years in a private orchard, from the second growing season until full production. Light spectra under photo-selective nets were measured on one sunny day of the third growing season at two distances from the net and in the two sides of the row using an array spectrometer; tree growth was evaluated every year, fruit yield and quality were assessed during the second and third year. The light spectra under the nets were modified according to net color. All tested nets reduced the ultraviolet A (UVA) wavelength to a similar extent. Trees under blue nets had fewer fruit per tree in the first and less kg tree^‑1 and fruit per tree in the second year. Black net results were intermediate in the second year while trees under red nets had more fruit per tree. No other differences were observed in the first and last year. Trees under red nets had less red-colored fruit, and the blue treatment was intermediate, in the first year. Trees under blue nets had less growth than trees under other net colors, but they did not show any photosynthetic stress. The results suggest that blue nets reduced peach tree vigor as reported by previous studies in other species, while yellow and red nets improved fruit production and quality. In conclusion, photo-selective plastic nets slightly influenced production and growth mainly in the first two years of application on young peach trees with limited specific and opposite results. It can be assumed that red and yellow nets might induce higher production and fruit quality and blue nets might determine less vigor and fruit quality.