<p>To explore the effects of different altitudes and crop cycle on the occurrence of sugarcane smut in the low-latitude plateau region of Yunnan, this study conducted a systematic investigation of smut incidence in the southern subtropical humid, southern subtropical semi-humid, and northern tropical semi-humid sugarcane growing areas of Yunnan. The results showed that there were significant differences in smut incidence among different regions, altitudes, and crop cycle in Yunnan. The smut incidence ranged from 4.94% to 16.44% across different regions, indicating that smut has occurred universally and caused severe damage in Yunnan. The incidence varied from 2.89% to 14.71% across different altitudes, exhibiting a decreasing trend with increasing altitude. For different crop cycle, the incidence ranged from 5.81% to 15.31%, showing an increasing trend as the crop cycle extended. Under the ecological conditions of Yunnan's low-latitude plateau, altitude and crop cycle were identified as the main sources of variation in smut incidence. Their interaction effect was not significant, whereas the respective main effects of both factors were statistically significant. Meanwhile, the contribution rate of variation to smut incidence of altitude (63.20%) was higher than that of crop cycle (28.81%). These findings provide a scientific basis for the rational distribution of elite sugarcane varieties and the scientific control of smut in the low-latitude plateau sugarcane regions of Yunnan.</p>