Abstract: In order to develop the effective technologies to prevent and control the twig blight disease of bayberry， it was studied that how conidia infected and disseminated， how the twig blight disease occured and spread in the whole year， and how the fungi distributed in bayberry plants. The conidia solution with concentrations of 2×101 to 2×106 mL-1 could infect bayberry mainly through the orifice and wound on the young shoots. The conidia had two peaks of infection， the whole May， the mid of June to the mid of July， respectively. The conidia could be captured throughout the year. There were 2 captured peaks， the mid of May to the mid of June， the end of August to the mid of October， respectively. The bayberry trees had new diseased shoots throughout the year， and the peak incidence was in the middle of September to the early of November. The twig blight disease had the centers， and the trees in the low altitude， water erosion serious position were infected firstly. The isolated fungal strains and DNA copy numbers of the diseased were 2-6 times of the healthy in a whole year. The pathogens could survive in the bayberry plants in the whole year with the most quantity in young shoots， but without obvious time peaks.

Key words: twig blight disease on bayberry, Pestalotiopsis versicolor ；Pestalotiopsis microspora ；conidia