| Summary: | 碩士 === 國立中興大學 === 農藝學系所 === 104 === Young leaves of tea (Camellia sinensis L.) in Taiwan frequently injured by pests, including green leaf hopper (Jacobiasca formosana L.). However, the latter induces leaves a special flavor and fragrance, and which is the characteristics of the tea so called “Oriental Beauty”. In this study, we investigated the population of green leaf hoppers appeared in tea garden, the results showed that the month of the appearance of the biggest population of green leaf hoppers is May. We also use four other tea varieties (Jinxuan, Chin-Shin Oolong, Hongyu, and Hongyun) to test the preference of green leaf hoppers infestation, and there is no difference among four tea varieties. By the way, the growth of four varieties of tea had no significant differences after infestation in eight weeks. Besides, only growth of Jinxuan and Hongyu had significant differences. After analyzing leaves (one bud with two younger leaves), we found that total polyphenols increased more while infestation levels get higher, especially for the small-leaf varieties. Analysis results showed that only caffeine in Chin-Shin Oolong increased more than 67% compared with non-infestated young leaves. After infestation by green leaf hopper, theanine had no significant differences among four varieties, and all of the catechins in tea varieties were increased, including epigallocatechin gallate (EGCG), epicatechin gallate (ECG), gallocatechin gallate (GCG), and catechin gallate (CG), especially EGCG. At the same time, we analyzed the infestated young leaves of Chin-Shin-Dapang which we sampled directly from the tea garden at the location of Oriental Beauty tea produced, to analyze the internal components and compared with four tea varieties we tested previously. The results showed that the contents of total polyphenols, caffeine, EGC, EGCG, ECG, GCG, and CG were increased when suffering from the high infestation, and these changes were the same among five tea varieties.
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