Effect of Photo-Selective Nets on Yield, Fruit Quality and Psa Disease Progression in a 'Hayward' Kiwifruit Orchard

The influence of the colour of photo-selective nets on Actinidia deliciosa yield, fruit quality and progression of the bacterial kiwifruit canker (Pseudomonas syringae pv. actinidiae, Psa) need to be characterised due to increasing use of these nets, mainly to protect from hail and storms. From May 2019 onwards, pearl (Pn), yellow (Yn) and grey (Gn) nets were installed permanently in a 'Hayward' kiwifruit orchard in NW Portugal and uncovered plants were used as the control. Compared to outside conditions for both seasons, the blue:red ratio and the mean air temperature were higher (mean increase of 12.7% and 0.6 degrees C, respectively) and the photosynthetic active radiation (PAR) was lower (10.8% less between budbreak and bloom) under the Pn. Crop yield, compared to the control, decreased by 40.3% under the three nets in 2020, and by 23.9% under the Yn and Gn in 2021. Yield and fruit grade under the Pn were similar to that of uncovered crops in 2021, and fruit grade was overall higher under the Pn compared to the Yn and Gn. Photo-selective nets did not affect the fruit quality parameters. Psa progression decreased under the Pn compared to the control during two months in both seasons, although this beneficial impact needs further evaluation.

Automated summary

This study investigated the influence of the colour of photo-selective nets on Actinidia deliciosa yield, fruit quality, and the progression of the bacterial kiwifruit canker. The results showed that different colours of nets had a certain impact on yield and fruit quality, with lower yield observed under yellow and grey nets, while the yield and fruit grade under pearl nets were similar to uncovered crops. Photo-selective nets did not significantly affect fruit quality parameters and had a reduced impact on the progression of the bacterial kiwifruit canker in both seasons.