sp. is a serious pest on Dendrobium Sw. in recent years. It had two or three generations one year with overlapped generations in Pu’er of Yunnan province. Both the adults and the larvae had two peaks of occurrence. The peaks for larvae took place in March to April and September to October, and in June and December for adults. The host plants were damaged mainly by its larvae. The larvae were stem borers, and adults damaged both stems and leaves. Dendrobium thyrsiflorum  was the most severely damaged. The number of the feeding adults in the afternoon (13:00～14:30)was obviously higher than those in the morning(8:30～9:30) and in the dusk(17:30～18:30). It was positively related to the average temperature. The adults preferred the leaves to the stems in the morning, and preferred the stems to the leaves in the afternoon and dusk.