Mulch-driven tolerance in potatoes: a climate adaptation tool for enhanced yields and plant defence under drought stress conditions

Climate change increasingly challenges potato production through intensified drought stress and emerging vector-transmitted diseases. This study evaluated straw mulch application as a climate adaptation strategy across three field seasons (2022–2024) in Bingen am Rhein, Germany, testing five potato cultivars under varying drought conditions and bacterial pathogen pressure from Pentastiridius leporinus , a vector of 'Candidatus Phytoplasma solani' and 'Candidatus Arsenophonus phytopathogenicus'. Complementary greenhouse choice-experiments investigated vector oviposition preferences on different soil types and mulch coverage.Field trials revealed significant year × variety interactions in yield responses to mulch treatment, with effects strongly correlated to drought severity. Under mulch treatment, Darling achieved a 119% yield increase during severe stress conditions (2022), while Almonda and Jule showed substantial responses to mulching (77% and 90% increases respectively in 2023). Mulch treatment significantly reduced bacterial potato tuber wilt incidence by 22% (p = 0.019) and reduced wilting symptoms by 29% (p = 0.072). The magnitude of mulch benefits correlated directly with drought severity, demonstrating greatest efficacy under high stress conditions. Controlled greenhouse choice-experiments provided insights into vector behavior, revealing that P. leporinus preferred straw-covered over bare soil (χ²=25.15, p < 0.001) and loam over sandy substrates (χ²=15.54, p < 0.001) for oviposition.These findings demonstrate that mulch operates through multifaceted mechanisms involving stress tolerance and complex plant-vector-pathogen interactions rather than simple vector deterrence. The net positive outcomes for both yield and disease management under drought conditions support strategic mulch deployment as a valuable climate adaptation tool, particularly when integrated with cultivar selection and environmental forecasting. This research provides the first comprehensive evaluation of cultivar-specific responses to mulch under combined drought and bacterial pathogen pressure, offering practical insights for sustainable potato production in changing climatic conditions.