Raspberry floricane dieback in northern Italy: the cane vigor influence and the evaluation of primocane basal cleaning management in double crop system

Rubus idaeus L. are increasing in the Piedmont, northern Italy due the high demand for red raspberries consumption from consumers. Intensive cropping has caused emerging cane diseases that affect raspberry production; the main symptoms are on the floricanes that show as brittle, snap off easily, died and with buds stunted development. Control and effective disease management are necessary to guarantee the quantitative and qualitative production. The aim of this work was to evaluate the symptoms on cane diseases of cultivar ‘Grandeur®’ in Piedmont (Cuneo province) where plantations intensive systems are developing. Two activities were carried out between 2020 and 2021. In the first year a disease rating scale with six classes was created (0 = no cane symptoms and 5 = high cane symptom) and in the orchard the floricanes were selected in function of pruned cane vigor (diameter >0.99 cm; <0.99 cm and control). Then, the canes were classified in relation to the disease symptoms and the vegetative data (total buds, open buds, number of flowers) and production data (harvest) were collected. In the second year the basal primocane defoliation effect was evaluated on the severity disease reduction. The healthier canes with better performance in terms of open buds, number of flowers and fruit harvested were those with the diameter <0.99. The basal cleaning management compared to the control did not show any important improvements in terms of harvested raspberries. In conclusion, this work increases the understanding of intensive raspberry cultivation in the Piedmont area suggesting possible changes in agronomic management strategies.