Phototaxis, population dynamics and the sex structure of Exolontha castanea Chang adults were investigated in in sugarcane fields using light traps equipped with a self-ballasted high-pressure mercury vapor lamp (SHMVL) and a frequency oscillation pest-killing light trap (FOPLT) from 2016 to 2019. Results showed that adults of E. castanea displayed phototaxis, and the number of female adults trapped accounted for more than 95% of the total, clearly evidenced that there were sexual differences in the phototaxis. The flight period of adults occurred from late April to late June, and multi-peaks were observed during this period. While the sex ratio (female/male) of the natural population approached 1: 1, these results indicated that the phototaxis of females caught was significantly higher than that of males, and it had nothing to do with the number of males and females in the field. Thus, we can conclude that the implementation of light traps could be an effective strategy for controlling E. castanea in the future, as it is the females that return to the sugarcane fields to lay their eggs.