Abstract
Botryosphaeria berengeriana f. sp. persicae was confirmed to cause circular to ovalshaped sunken lesions around lenticels of peach trees, in addition to blisters on shoots, and gummosis. The blisters developed on 1 or 2 yr old shoots, and sunken lesions were formed on shoots older than 3 yr. Among 1 yr old shoots, most of blisters were formed on water sprout shoots, followed by intermediated type of shoots, whereas few blisters were formed on weak shoots which will bear fruits in next year. On water sprout shoot, many blisters were formed at basal part. The gummosis was found in rainy season on shoots older than 2 yr. Inoculation with conidia of the pathogen to peach trees in May, June or July caused more serious infection than those in April, September, or October. The symptoms produced by inoculation on 1, 2 and 3 yr old shoots were identical with those on naturally infected trees. Branches inoculated in April, May, June or July developed symptoms from late August to early September, those inoculated in August or September developed symptoms from October to December, and those inoculated in October developed in February of the next year. Increase in blisters occurred twice, i.e., in autumn and from spring to early summer of the next year. As a result of the experiment using infected branches as the inoculum, positive correlation was found between number of blisters formed and the amount of rain fall, and also the number of conidia trapped.
