The role of wind in the spatiotemporal distribution of strawberry powdery mildew in high-tunnel growing systems

Strawberry powdery mildew, caused by Podosphaera aphanis, is a major fungal disease affecting strawberry cultivation worldwide. Its rapid lifetime cycle and ability to spread under a wide range of favourable conditions make early detection and management particularly challenging. Understanding the impact of environmental factors on disease dispersal is crucial for improving forecasting and control strategies. This study investigated the spatiotemporal distribution of strawberry powdery mildew in a high tunnel with a specific focus on wind as a primary driver of inoculum release and dispersal. Disease spread was monitored from a single inoculum source, both under natural wind conditions and with minimized wind influence to assess pathogen dispersal efficiency under varying wind speeds. The infection rate was modelled using a Zero-Inflated Negative Binomial (ZINB) model according to airborne conidium concentration and distance from the inoculum. Results show that disease spread follows an exponential decay pattern with a dispersal rate of 1.65 m day⁻¹. Temperature and relative humidity significantly influence conidium release, with wind as the most critical factor driving pathogen dispersal. Wind contributes to the formation of heterogeneous infectious hotspots along the tunnel, shaping the spatial and temporal distribution of the disease. However, wind speed had no significant impact on quantitative disease progression, highlighting high pathogen dispersal efficiency even under low wind conditions.