Study on Red Spot Disease of Peony Tree

The red spot disease was one of the important diseases of peony tree and was widely spread in Heze peony tree cultural region in Shandong Province. The infecting rate was about 50% in most peony gardens, and 90% in seriously infected garden. 512 isolates were obtained from 384 samples of 8 batches. by screening, purifying and re-inoculating test, The pathogen was identified as Cladosporium paeoniae according to its cultural and morphological characteristics. The occurrence of disease was closely correlated to the initial infection sources and species of peony tree. Some fungicides, such as the 50% carbendazim, 70% thiophanate-methyl were proved to be effective to control the red spot disease. 800-fold of the fungicides had about 90% efficiencies when spreading for 4 times from middle March to middle July and the infection index could be controlled lower than 5.