Integrated control of aerial fungal diseases of olive

Abstract

Foliar and fruit fungal diseases are responsible for severe yield losses in olives (Olea europaea L.) in most olive-growing areas around the world. Among the most important are leaf spot, anthracnose, cercosporiosis and drupe rot, respectively caused by Fusicladium oleagineum, Colletotrichum spp., Pseudocercospora cladosporioides and Botryosphaeria dothidea. Symptoms vary from tree defoliation, twig dieback, premature fruit fall and drupe rot, which can completely destroy olive production and reduce olive oil quality. Copper-based products and a few other compounds represent almost the only fungicides used to date to control aerial fungal diseases of olive. Moreover, although still permitted, the European authorities would like to see a ban on copper fungicides in conventional and organic farming across Europe, which would have a major impact on disease management in olive production. Under Directive 2009/128, the Sustainable Use Directive, National Action Plans for reductions in pesticide use, and the implementation of Integrated Pest Management on all farms in member states were reviewed by the European Union at the end of 2014 and became mandatory throughout member states. Extensive field trials conducted in southern Italy in recent years demonstrate that aerial fungal diseases of olive can be effectively controlled in an integrated management approach, using appropriately timed application of traditional fungicides and organically approved plant protection compounds, such as sulphur. Particularly, a new sulphur-based product, Thiopron®, was as effective as traditional fungicides in controlling both olive cercosporiosis and drupe rot caused by different fungal species.