Association of temperature and relative humidity with leaf rust and stripe rust incidence and severity in wheat across major wheat-growing districts of Punjab, Pakistan

Wheat ( Triticum aestivum L.) is the principal staple crop of Pakistan, with Punjab contributing approximately 75% of the country's total wheat production. Leaf rust ( Puccinia triticina ) and stripe rust ( Puccinia striiformis ) are among the most detrimental diseases affecting wheat yield in the country. This study aimed to assess the influence of temperature and relative humidity on the incidence and severity of both diseases in eight major wheat-producing districts of Punjab during the 2024–2025 cropping season. A field survey was conducted at 20 wheat fields with 160 locations at three critical growth stages of the wheat crop and the survey included the commercially cultivated wheat cultivars Akbar-19, MH-21, and Fareed-06. Disease and climatic data were analyzed using multiple linear regression models. The analysis revealed that temperature was the most influential climatic variable, and Regression coefficients indicated that disease incidence increased by approximately 4.3–12.7 percentage points per 1°C increase depending on district. The effect of relative humidity was insignificant or very limited in most of the district-level models. Disease responses varied among districts, reflecting regional differences in climatic conditions. Among the cultivars studied, Akbar-19 was the most susceptible cultivar while Fareed-06 showed lower levels of disease incidence and severity. Overall, these findings indicate that temperature plays a major role in driving wheat rust epidemics in Punjab highlight the need to integrate temperature-based forecasting models along with resistant cultivars for climate-smart wheat disease management in the context of future climate change scenarios.