危害龙眼的天牛有龟背天牛和星天牛两种,是龙眼的重要害虫。天牛以幼虫蛀食枝干,以成虫取食枝梢皮层,导致枝条干枯,新梢枯死,甚至整株树死亡。每年的3～7月,是天牛幼虫危害最多的时节。7～8月则是成虫取食危害时期。龟背天牛的卵孵化后,幼虫向树皮下蛀食,慢慢蛀入木质部,然后自上往下在木质部中危害,每隔一定距离必有一排粪孔,排出虫粪呈短圆柱形, Hazard endangered longan have turtles and celastrus two, is an important pest of longan. Cerambycidae eat larvae to dry branches, feeding adult shoots cortex, causing the branches dry, dead shoots, and even the entire tree died. Every year from March to July, it is the most harmful season for the larvae of the cerambycium. July to August is the period of adult feeding hazards. After hatching eggs of turtle beetle, the larvae eaten under the bark and slowly eroded the xylem, then harms in the xylem from top to bottom. There must be a row of manure holes at regular intervals,