Since 2020, the bacteria Erwinia amylovora is no longer considered a quarantine pest in the European Union and Switzerland, even though fire blight is still responsible for damaging losses for producers. In addition to a low range of products registered in Switzerland against this disease and a ban of antibiotics since 2016, there is also a government incentive to reduce the use of plant protection products and the withdrawal of certain products in neighbouring countries. In this context, it is essential to gain experience and create a reliable knowledge base in fire blight control using alternative and sustainable strategies to support Swiss pome fruit production. For this reason, the Swiss research institute Agroscope, as part of the HERAKLES Plus project, continues to conduct orchard trials every year, where different products (registered or in pending registration) and combinations of products are tested. The trials are conducted under biosafety guidelines in an orchard completely enclosed by insect netting on three-year-old potted apple trees. Trees are directly inoculated with the E. amylovora bacteria during flowering and bumblebees spread the disease to neighbouring trees, which are treated using different strategies. The efficacy of the variants is compared to untreated trees and trees treated with Blossom ProtectTM (Aureobasidium pullulans). The results from previous years will be presented at the conference.
