Global Risk Assessment of the Invasive Insect Thaumatotibia leucotreta to Citrus Based on its Potential Distribution

The false-codling moth (FCM), Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), is a globally recognized quarantine pest responsible for substantial economic losses in the southern African citrus industry. Driven by international trade and climate change, FCM poses a potential threat to regions beyond its native range. In this study, we employed the MaxEnt model to predict suitable habitats for FCM under near-current and future climate scenarios based on 141 global occurrence data and 19 bioclimatic variables. The model performed excellently with an AUC of 0.965. The key bioclimatic variables affecting FCM distribution were isothermality (bio3), maximum temperature of the warmest month (bio5), mean temperature of the driest quarter (bio9), and annual precipitation (bio12). Under near-current climate conditions, the total suitable habitat was estimated at approximately 2575.03 × 10⁴ km². Highly suitable areas were located in Central America, the Caribbean, South America, Europe, Central and Southern Africa, and Central and Southeast Asia. Future climate projections indicated a general decrease in suitable habitats, with the most contraction under the SSP5-8.5 scenario by the 2070s, where suitable areas are projected to shrink by 11.23%. The overlap between FCM habitats and global citrus cultivation reached 714.02 × 10⁴ km², with major hotspots in Africa (e.g., Tanzania, Angola; 297.47 × 10⁴ km²), South America, Asia, and Europe. Given the extensive overlap and the severe damage caused by FCM, enhanced quarantine measures and integrated pest management strategies are urgently required to mitigate the risk of its global spread and establishment.