Pathogen Identification And Control Of Apple Blue Mold During Storage Period In Hebei Province

One hundred and thirty four rotten apple samples were collected from Baoding, Shijiazhuang and Cangzhou city of Hebei province. Among them, there were 84 rotten apple samples infected by Penicillium spp. accounting for 62.69% of the total samples. There were 38 rotten apple samples infected by Alternaria spp. and 6 rotten apple samples infected by Botryis spp. accounting for 28.36% and 4.28%, respectively. Accordingly, Penicillium spp. was the main pathogen on apple during storage time. And through investigation, the wound of apple surface was the main infection apporoach of blue mold.Fourty-two isolates of Penicillium spp. were isolated from rotten apple samples. Those isolates were identified according to the cultivation characters in different media including CYA, MEA, and G25N. In the further step, Penicillium spp. were identified according to the morphology of conidiophore, the size and shape of conidia. Four species of Penicillium were identified. They are P. expansum (LK.) Thom, P. cyclopium Westling, P. crustosum Thom and P. islandicum Sopp and their isolation frequency were 71.4%, 16.7%, 7.1% and 4.8% respectively. Therefore, P. expansum is the main pathogen of apple blue mold during storage time in Hebei province.Four species of Penicillium spp. were isolated from apple fruits. Fuji apple fruits were selected as the host for testing pathogenicity of those pathogens. The results indicated that the pathogenicity of the four species was significantly different. P. expansum was the most toxic and P. islandicum the least toxic to Fuji apple fruits. Temperature affected the length of incubation period of the pathogens. The incubation period of the disease was longer when the pathogen was cultivated at 4℃ than at 25 ℃. And incubation periods of different Penicillium pathogens were different. The incubation period of P. expansum on Fuji apple fruits was the longest. In contrast, the incubation period of P. islandicum on Fuji apple fruits was the shortest.The range of the temperature for mycelial growth of four pathogens was from 3 ℃ to 35℃. The optimum temperature was 25 ℃. The optimum temperature for the conidial germination was from 15℃ to 20 ℃. The conidia of four pathogens did not germinate at 3℃ and 35℃ after cultivating for 72hrs. The range of the pH value for mycelial growth of four pathogens was from 3 to 12, and the optimum pH was 9. For P. expansum, P. cyclopium and P. crustosum, the optimum pH value of the conidial germination was from 3 to 7. But the optimum pH value of the conidial germination of P. islandicum was from...