关键词: 茶拟盘多毛孢菌, 茶褐斑拟盘多毛孢菌, 生物学特性, 致病表现

Abstract: In this paper, symptoms caused by P. theae and P. guepinii of Pestalotiopsis genus on the leaves were compared, and the colony, morphological features and biological characteristics of the two pathogens were observed. The results indicated that, in the early stages the symptoms between two pathoens only showed a small difference. However, symptoms were marked distinction in the later stage. The points on tea leaves caused by P. theae was brown and with concentric ring and protruding black points, the symptoms of gray leaf spot was grey and scattered with small black points. The colonies of P. theae fungus appeared concentric ring, appendages of conidium amounted to 2~4. The colonies of P. guepinii fungus appeared wavy uplifting, appendages amounted to 2~5. The optimal temperature for spore germination of the both pathogens was 25℃, with the germination rate 87.5% and 86.1% respectively. The tea juice promoted the spore germination and sporulation. The spore germination, hyphal growth and the sporulation were inhibited obviousely by strong light. The optimal temperature for hypha growth of P. theae was 26~28℃, and the P. guepini was 24~25℃. PDA was the optimum medium for hypha growth of the two pathogens and the PSA supplemented with 200 g/L tea juice was suitable for their sporulation. The optimum pH for hypha growth of the P. theae was 6.0 and the P. guepini was 7.5. The spore suspension of two pathogens with tea juice was inoculated on tea leaves at different age which were slightly scraped on the surface or not. Results showed that wounds were helpful to the infection of P. theae spores and penetrated via the bud, and tender leaves were favorable for infection directly, but also infected the wound mature leaf. P. guepinii spores could only infected the bud, tender leaf and mature leaf that after scraping.

Key words: Pestalotiopsis theae, Pestalotipsis guepinii, biological characteristics, pathogenic showed