Bladsvampevarsling

Conclusion

Rust has been the dominant leaf disease in 2020. The attacks began in late July and with a relatively weak development until mid-August, after which the attacks increased until harvest. Powdery mildew attacks have begun 1-2 weeks later than rust, and the attacks have been relatively weak. The attacks of Ramularia have been very weak. Cercospora has been less widespread than in 2019, but more widespread than in previous years.
In the leaf disease warning service, 20 fields have weekly been monitored for infestations in a number of varieties. The first attacks of rust have been seen week 30 (July 20-26), and treatments was recommended in fields with incipient attacks. Where first treatment has been performed in week 31 and where harvest has been planned for after mid-October, a follow-up treatment in week 34 has been recommended, where fresh rust pustules could be seen. For fields with lifting later than mid-November, a 3rd treatment could possibly be followed up 3-4 weeks later.