The production of apples in Japan has been severely affected for long time by apple canker caused by the infection of Valsa ceratosperma. 1) This disease!, Z) is one of the most severe problems in cultivation of apple trees. The infection occurs first in mechanically injured parts and necrotic areas of the bark, Z) and then gradually invades the trunk. Therefore, curative effects of many commercial fungicides could not be expected to be due to the failure of ...
