Assessing the Influence of Shifting Thermal Regimes on Tomato fruit borer, Helicoverpa armigera (Hubner) in the Eastern Himalaya: Implications for Pest Management Strategies

Abstract

Abstract Climate change especially the change in the temperature is having profound impacts on the pest population of tomato, a crucial commercial crop, in the Eastern Himalayan Region of India. To understand the impact of different thermal regimes on the fruit borer of tomatoes, field experiments were conducted at three locations with altitudes ranging from <500 to >1500 meters. At lower altitudes, fruit borer incidence was found to commence earlier in the season (5th - 18th March) and had a higher peak population (1.47 to 1.73 larvae/plant) causing more fruit damage (26-29%) as compared to the highest location (~9%). Correlation analysis indicated that maximum and minimum temperatures had significant positive impacts on the H. armigera incidence and fruit damage. Climatic datasets indicate an increase in the temperature of the region during the tomato growing season, thereby increasing the risk of fruit borer impact. As an adaptation option, we evaluated eight different tomato varieties/genotypes and studied biochemical parameters to understand their tolerance. Results showed a strong positive association of fruit borer incidence with total soluble solids and lycopene whereas negative association with acidity. Among the varieties/genotypes, Cherry tomato (7.62%) and MT-2 (10.04%) had relatively lower fruit damage; MT-3 (50.92 t/ha) and MT-2 (50.57 t/ha) consistently yielded the highest across all locations. Hence, the selection of appropriate genotypes and the development of varieties with suitable characteristics hold the key to fruit borer management. These findings can be valuable for pest management, understanding its further spread, and agricultural planning in the region.