Pubblicazioni

One of the reasons for the poor marketability on the Swiss market of the chestnuts produced in Ticino in the immediate post-war period was the high rate of infestation by carpophagous insects. In the 1990s, when interest in chestnut groves and chestnuts in southern Switzerland was revived, it felt necessary to carry out a survey on this aspect. The present study concerns two pairs of chestnut orchards (managed and abandoned) in each of the three chosen localities (Biasca, Torricella and Vezio) where the phenology of the main carpophagous insects and their impact on the production of burrs and chestnuts were monitored. The composition of the carpophagous populations has not changed substantially since the 1950s. C. fagiglandana is still absent from the chestnut environment, while Cydia splendana and Curculio elephas are the main fruit pests. Pammene fasciana mainly infests burrs only, causing an average of 12.8% early drop, ranging from 5.9% (Biasca,managed orchard) to 30.9% (Vezio, abandoned orchard). The infestation rate of ripe fruit is very high and varies from 44% (Vezio) to 50% (Biasca) in managed orchards, while it shows much more marked differences in abandoned ones, ranging from a minimum of 24% in Vezio to a maximum of 86% in Torricella. The differences are more marked among sites with respect to the type of orchard management, which may be interpreted as the result of the very extensive management of the groves in the 1990s and the related lack of significant differences with respect to the abandoned ones.