茶饼病菌的侵染及其生物学特性

1.在20℃左右,用茶饼病菌(Exobasidium vexans Massee)的担孢子接种于感病的茶树品种上,2小时后叶面上的担孢子开始萌发(萌发率3.1％),4小时后的萌发率为7.9％,24小时则高达21.3％。芽管直接由表皮侵入。气温在18～20℃的条件下,从病菌的侵入到症状的出现为10～13天;在20～23℃时,则为8～10天。 2.担孢子在茶叶面露水中萌发率最高。萌发适温为20～25℃,相对湿度达90％以上才能萌发,而以在水滴中最适。在散射光下萌发率较高。担孢子寿命在18～23℃条件下,仅为4～7天。病斑在3～4天内有再产生担孢子的能力。 3.在茶树生长期间,担孢子全年可产生8～9次。担孢子借气流传播,每天以凌晨1:00—5:00时捕捉的孢子量最多。

THE INFECTION OF EXOBASIDIUM VEXANS MASSEE AND ITS BIOLOGICAL CHARACTER

Susceptible varieties of tea are inoculated with the basidiospores of Exobasidium vexans Massee at 20℃. After 2 hours, the basidiospores on leaves began germinating (germination rate 3.1%). The germination percentage is 7.9% after 4 hours, but it becomes as high as 21.3% after 24 hours. The germ tube directly penetrates the surface of leaves. At 18—20℃, the incubation period is 10—13 days; at20—23℃, 8—10 days. It was found that germination rate was high in the dew on tea leaf surface. The optimum temperature range for germination was 20—25℃. They can germinate above R. H. 90%. but most rapidly in water drops. The germination rate is higher under natural scattering light. The longevity of basidiospores is about 4—7 days at 18—23℃. The lesions are able to produce basidiospores within 3—4 days. In growing period of tea brush, basidiospores appear 8—9 times in a year. They are transmitted by air current. More basidiospores are trapped at 1—5a.m.