Interactions of Insect Pests, Diseases, and Sub1 Rice Varieties Across Agro-Climatic Zones in Assam: Insights for Strengthening Resilient Rice Cultivation

Thanga Suja Srinivasan^1,2*Panneerselvam Peramaiyan^1*Ainara PeñalverCruz³Suryakanta Khandai¹Vipin Kumar¹Vivek Kumar¹Mrinal Saikia⁴Kalyan Pathak⁴Rupam Borgohain⁴Kanwar Singh¹Shabrin Sultana Ahmed⁴Gayetree Goswami⁴Jutika Das⁴Virendar Kumar¹Sudhanshu Singh¹Ashok Bhattacharyya⁴

• ¹International Rice Research Institute (India), New Delhi, National Capital Territory of Delhi, India
• ²World Vegetable Center South Asia, Patancheru, Telangana, India
• ³Institute of Agrifood Research and Technology (IRTA), Barcelona, Catalonia, Spain
• ⁴Assam Agricultural University, Jorhat, Assam, India

This study investigates the prevalence and interaction of insect pests and diseases across agro-climatic zones of Assam that are deployed with submergence-tolerant (Sub1) rice varieties. Utilizing data collected for two years (2020 and 2022) from farmers' fields, the research provides novel insights into how host genotype and climatic zones influence insect pests and disease prevalence under real-world conditions. The results reveal significant variability in insect and disease incidence across different agro-climatic zones and among rice varieties. The Central Brahmaputra Valley (CBV) zone exhibited a higher prevalence of insect pests such as the L. acuta, S. incertulas, and C. medinalis, while the Lower Brahmaputra Valley (LBV) zone demonstrated increased disease incidence, particularly of M. oryzae and B. oryzae. Similarly, varietal responses varied across agro-climatic zones; Bahadur-Sub1 exhibited comparatively lower insect and disease incidence, whereas Bina dhan 11 showed higher L. acuta and C. medinalis incidence across zones. Principal Component Analysis underscored zone-specific associations between insect pests and diseases, emphasizing the complex interactions among host plants, agro-climatic conditions, and insect-pest population build up. Temporal variation was also observed, with differences in insect pests and disease prevalence between the two years, highlighting the impact of macro and micro-climatic factors. These findings suggest continuous monitoring and development of adaptive, zone-specific insect and disease management strategies that can minimize insect-pest adaptation and enhance the resilience and productivity of rainfed rice ecosystems in Assam.