First report of ‘Candidatus Arsenophonus phytopathogenicus’ on maize
The γ-proteobacterium ‘Candidatus Arsenophonus phytopathogenicus’ was first associated with ‘Syndrome des basses richesses’ (formerly EPPO Alert List), an emerging disease of sugar beet (Beta vulgaris) in the EPPO region (EPPO RS 2025/074). It is transmitted by a planthopper, Pentastiridius leporinus (Hemiptera: Cixiidae). It was recently found associated with other crops: potato (EPPO RS 2023/209, RS 2025/073) and onion (RS 2025/072).
In summer 2025 ‘Ca. Arsenophonus phytopathogenicus’ was first detected by molecular tests in maize plants (Zea mays) in Germany. Plants showed patchy premature drying, reddish discoloration of leaves and midribs, poorly filled or aborted ears, and malformed kernels. Samples had been collected in Baden-Württemberg, Hessen and Rheinland-Pfalz.
It may be noted that P. leporinus is already known as a vector of maize redness ('Candidatus Phytoplasma solani' - formerly EPPO Alert List).
Sources
Benaouda S, Witczak N, Kaufmann T, Löffler D, Pfitzner H, Dettweiler A, Lee K-Z, Lang C (2026) First report of ‘Candidatus Arsenophonus phytopathogenicus’ in maize (Zea mays L.) in Germany. Plant Disease (early view) https://doi.org/10.1094/PDIS-07-26-1454-PDN.