In Northern Ireland (United Kingdom), wilt symptoms were observed during summer 2022 on lettuce (Lactuca sativa cv. Amica) grown under a greenhouse in county Armagh, reporting from EPPO says.
Affected plants initially showed stunting, followed by wilting and yellowing of lower leaves. Orangebrown discoloration of vascular tissue in the taproot of affected plants was also observed. Molecular (PCR, sequencing) and pathogenicity tests confirmed the presence of Fusarium oxysporum f. sp. lactucae (formerly EPPO Alert List) Race 1 in symptomatic samples (van Amsterdam et al., 2023).
Fusarium wilt on lettuce is primarily a soilborne disease and can survive in soil and crop debris. It is one of the most common plant diseases of lettuce, which damages lettuce's roots through covered and open cultivation, resulting in significant yield loss or even complete crop failure, which is why wilt has seriously affected several European countries. The virus is very persistent. In the Netherlands and Norway, the acreage of soil-born greenhouse lettuce is seriously reduced due to the virus.
Several breeders are offering resistant varieties.