The Rising Risk of Stem Borers in Gilan's Rice Fields Due to Climate Change: A Case Study of Chilo suppressalis

The northern provinces of Iran along the Caspian Sea coast, with their favorable climate and ample water resources, host extensive rice fields that are vital to both local livelihoods and the national economy. Chilo suppressalis, a major pest species, is estimated by the Agricultural Organization of Gilan province to cause a 30–50% reduction in crop yield and a decline in product quality. Despite its significance, the potential impact of climate change on this pest has not been thoroughly studied in Iran, leaving a critical knowledge gap. In this study, we address this gap by projecting the future distribution of C. suppressalis under two climate change scenarios (SSP2-4.5 and SSP5-8.5) for the year 2070. The results confirm the pest’s current widespread presence in the rice fields of Golestan, Mazandaran, and Gilan provinces, aligning with recorded data from the Agricultural Organization. However, projections indicate a sharp decline in the species' spread in eastern Mazandaran and Golestan, with a shift toward western regions. Conversely, Gilan province is predicted to experience both stability and an expansion of suitable habitat for the pest. As C. suppressalis is highly sensitive to extreme temperature fluctuations, preferring a range of 25–32 °C, these distribution shifts are consistent with expected climate impacts. To mitigate potential economic losses, it is imperative to implement proactive management strategies to address this issue promptly.