<正>杉木针叶上炭疽

Anthracnose caused by Glomereila cingulata (Ston.) S. et S. is a common disease of Chinese fir (Cunninghamia lanceolata) in south China. Latent infec tion in needles due to the causal fungus was studied in 1983~1984. The results showed: ( 1 ) The latent infection in needles is different from various parts of the crown and various locations on a twig or a needle. ( 2 ) The infection in current needles occurs initially in the middle of May and reaches to the maximum in the late August, and stops when the average temperature of a period of 15 days is below 10癈. (3) The percentage of latent infection increases with higher site class of Chinese fir plantation and the damage of the disease decreases with it. ( 4 ) The symptom of the disease develops in the early April to the late June on the tip of the last year twig and the severity is non-correlative with the rate of latent infection. ( 5 ) Higher reducing sugar content in needles seems the effective factor for the latency broken by the causal fungus.