Temporal Dynamics of Sapota Pest Damage and Phytophthora Disease: Insights from Time Series and Machine Learning Models

Meenakshi Malik^1*Niranjan Singh^2*Amoghavarsha Chittaragi³D Raghavendra²Balanagouda Patil⁴BACHU LAKSHMI MANISHA²

• ¹National Research Centre for Integrated Pest Management, New Delhi, India
• ²ICAR - National Research Institute for Integrated Pest Management, New Delhi, India
• ³University of Agricultural Sciences, GKVK, Bangalore-560 065, Bangalore, India
• ⁴3Keladi Shivappa Nayaka University of Agricultural and Horticultural Sciences, Iruvakki, Sagar – 577412, Karnataka, India

This study investigates the influence of climatic factors on pest damage and disease severity in sapota (Manilkara zapota L.) cultivation from 2012 to 2022 using a combination of statistical and machine learning models. Data were collected on key pests, including bud borer (Anarsia achrasella Bradley) and seed borer (Trymalitis margarias Meyrick), and the Phytophthora disease (Phytophthora sp.), alongside weather variables such as maximum temperature, minimum temperature, relative humidity, and rainfall. Trend analysis revealed fluctuating patterns in bud and seed borer damage, likely influenced by varying climatic conditions and pest management practices, while Phytophthora disease severity remained relatively stable.Correlation analysis indicated complex interactions between weather variables and pest or disease dynamics, with notable correlations between rainfall and bud borer damage (r = 0.69), and minimum temperature and Phytophthora severity (r = 0.64). Time series models, including ARIMA, SARIMA, and VAR, were employed to forecast future trends. The ARIMA model provided the most accurate forecasts for bud borer damage (MSE = 8.03) and Phytophthora severity (MSE = 0.20), while the VAR model performed best for seed borer damage (MSE = Field Code Changed Field Code Changed 17.96). Additionally, a Random Forest analysis identified minimum temperature as the most critical factor affecting bud borer damage and Phytophthora severity, while relative humidity was most influential for seed borer damage. The findings underscore the significant role of climatic factors, particularly temperature and humidity, in shaping pest and disease outcomes in sapota cultivation. This study provides valuable insights for developing targeted pest and disease management strategies that consider the dynamic effects of weather variables.