Abstract
The bacterial blossom blight of kiwifruit has been found widely in main kiwifruit growing areas of Nagasaki Prefecture, Japan. The disease occurred from the end of April to the middle of May in every year. Field observation from 1983 to 1989 revealed that the disease became very severe in alternate years. It was found by t-test analysis that there was a significant relation between the incidence of the disease and the precipitation at the leaf falling stage and the sprouting stage of kiwifruit. All severely infected flower buds either dropped off or produced malformed fruits without any healthy fruit production. Only 7% of moderately infected flower boils and 11% of slightly infected flower buds turned to healthy fruits. In kiwifruit growing fields, where flower infection rate was more than 46%, the average fruit production was less than 2.5 tons per 10 are.
