Simulation of climatic change impact on crop-pest interactions: a case study of rice pink stem borer Sesamia inferens (Walker)

Abstract

As climatic change impacts would depend upon complex interactions between climatic and biological factors, crop simulation models would play an important role in predicting such an impact. Present study thus aimed at simulating climatic change impacts on crop-pest interactions through a coupled crop-pest model. Based on temperature-dependent development of pink stem borer, Sesamia inferens (Walker) at six constant temperatures viz., 18, 21, 24, 27, 30, 33 and 35±1 °C, thermal constants for eggs, larvae and pupae were determined as 47.6, 700 and 166.7° days, respectively through a linear model with corresponding lower development thresholds being 13.8, 10.6 and 12.7 °C. Besides, optimum temperature and upper developmental threshold, respectively were found to be 34.6 and 36.2 °C for eggs, 34.5 and 36.4 °C for larvae, and 31.7 and 37.0 °C for pupae of the pink stem borer through a non-linear model. Based on the thermal requirements, and biotic and abiotic mortalities, a mechanistic holometabolous population simulation model for S. inferens was developed and coupled to InfoCrop-rice model. This coupled InfoCrop model could satisfactorily simulate the PSB dynamics and crop-pest interactions. Validated model was used to simulate the impacts of climatic change on S. inferens population and rice crop in accordance with four ‘standard special report on emissions scenarios’, A1, A2, B1 and B2. Simulations revealed that S. inferens population would decline to the extent of 5.82–22.8%by 2020 and 19.0–42.7%by 2050 under Delhi conditions. Following decline in pest population, S. inferens induced yield losses also revealed a declining trend under changed climate. The coupled crop-pest model can be easily adapted to diverse agro-environments and applied to simulate the pest dynamics and crop losses under location-specific situations.