Modeling the impact of integrated intervention strategies on early blight dynamics in tomato crops

The early blight disease in tomatoes, caused by Alternaria solani , seriously affects tomato production. Traditional disease controls primarily use fungicides, which can be costly and environmentally unfriendly. Notably, this study aims to reduce the use of fungicides by integrating other intervention strategies, such as mulching and shading, to control disease progression, sporulation, and transmission rates. A nonlinear mathematical model incorporating these factors and all population classes was formulated, and then the disease-free and endemic equilibrium was analyzed. The next-generation method was used to determine the effective reproduction number ( R e ), which is a key tool in analyzing disease dynamics for both disease-free equilibrium and endemic equilibrium. The model stability was analyzed both locally and globally for the Disease-Free Equilibrium. The relative importance of parameters is assessed through sensitivity analysis, employing the Partial Rank Correlation Coefficient method. The numerical simulations were performed using MATLAB software to evaluate the impact of interventions on critical parameters, such as the effective reproduction number ( R e ), sporulation rate ( σ ), transmission rate ( β e ) and disease progression rate ( ω ). The results show that mulching and shading effectively suppress fungal Alternaria solani sporulation and transmission rates by regulating soil moisture and temperature, and the fungicide application slows disease spread. The best control is achieved by combining all three interventions, diminishing the effects of temperature and rainfall, key environmental factors influencing disease spread.