Mulch-Driven Tolerance in Potatoes: A Climate Adaptation Tool for Enhanced Yields and Plant Defence under Drought Stress Conditions

Abstract Climate change increasingly threatens potato production through intensified drought stress and emergence of vector-transmitted diseases. This study evaluated straw mulch application as a dual-purpose climate adaptation strategy to enhance potato performance under drought conditions and reduce the incidence of bacterial potato tuber wilt (BPW) caused by ‘ Candidatus Arsenophonus phytopathogenicus’ and ‘ Candidatus Phytoplasma solani’, transmitted by the planthoppers Pentastiridius leporinus and Hyalesthes obsoletus . Field trials conducted from 2022 to 2024 in Bingen am Rhein, Germany, tested five potato cultivars under mulched and unmulched conditions. Complementary greenhouse choice experiments investigated oviposition preferences of P. leporinus in response to soil type and mulch cover. The magnitude of mulch benefits correlated directly with drought severity, demonstrating greatest efficacy under high-stress conditions. Mulch application increased tuber yield by 33% overall, though effects varied significantly across years ( p = 0.003) and cultivars ( p = 0.006), with cultivar Darling showing exceptional drought responsiveness (119% yield increase under severe drought conditions). Mulch significantly reduced rubbery tuber incidence by 22% ( p = 0.019) and showed marginal reduction in wilting symptoms (29%, p = 0.072). In contrast, greenhouse experiments revealed mulch significantly increased vector oviposition ( p < 0.001), particularly at the straw surface layer. These findings demonstrate that mulch operates through complex ecological pathways that buffer drought stress and enhance disease tolerance despite increased vector reproduction. 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 drought-responsive variety selection and precision management frameworks that balance enhanced vector habitat with improved plant resilience under combined abiotic and biotic stresses. 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.