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This experiment was carried out to determine damage of persimmon tree injured by katydids and their occurrence. The results obtained were as follows: Both the most active egg-hatching rate and the greatest number of hatching-eggs were found on the injured branch soaked at earlier date. Eggs of katydid were hatched within 24days after soaking. In 1992 and 1993, the highest egg-hatching rate was found between 2 to 7 days after soaking. In contrast, the greatest rate was observed between 14 to 19 days after soaking in 1994. Damage injured by the katydids was more serious in the border region than in the central region of the orchard. Injured branch by katydid was more found at high angles closer to right angle. The length of injured part was 8.0, with was 0.42, and depth was 0.42. Generally there was a decreasing trend in length of branch, number of fruits, and number of leaves grown on the injured two-year olds branches. The content of carotenoids and chlorophylls in the fruits and leaves of damaged branches were 35.79 ㎎/100 g f.w. and 1011 ㎍/g f.w, respectively. The corresponding values in the undamaged branches were 27.75 ㎎/100 g f.w. and 802 ㎍/ℓ g f.w.
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