关键词: 柠檬, 黑星病, 病原菌

Abstract: A pathogen of black spot of citrus limon is primary identified by some observations and fungi cultivations of slices of ground infested leaves or fruits. The pathogen belongs to Phoma sp. and lives through the winter in conidiophores for generations. In the middle and end of April it starts to fly and reaches the highest peak in the middle of May. After the conidiophores matured they move to new-borne leaves or fruits of citrus limon to re-infest. The ascosphores of sex generation are matured and moved in a large quantity at the beginning of June. It is also recognized that the invading time of Phoma sp. is at the middle of May by a bagging trial and it also is the best time to control. As regard of controlling technologies, the clearness of ground dead branches and leaves, and the usage of some of high-effective and low toxin fungicides can reduce the quantity of winter generations in an apple orchard. A trial result has been got, that is a specialized fertilizer for citrus limon can increase the anti-disease capacity of trees and at the same time can reduce 30 percent of injury rate on fruits. Another controlling measure founded is to spry fungicide to crown one time every 15 days from the middle of May, two times each year, and the controlling effective rate can reach 80 percent or above.

Key words: citrus limon, black spot, pathogen