Identification, Biological Characteristics of Pestalotiopsis diospyri and Its Sensitivity to Fungicides

摘要

Persimmon canker disease on stems caused by pathogens affects its growth and yield, leads to economic losses, thus it is important to investigate the pathogen in detail to find an effective control method. In this paper, samples from diseased persimmon trees in Yunnan were collected to isolate and purify the pathogen, and its biological characteristics were studied. In detail, its morphology was observed and molecular identified. The effects of different carbon and nitrogen sources, temperature, pH and light condition on its growth were analyzed, and the toxicities of 6 fungicides to the pathogen were compared. In the results, the pathogens were identified as Pestalotiopsis diospyri, the optimum conditions for its mycelium growth were on persimmon stem decoction medium, temperature 30 degrees C, light illumination for 24 h and pH at 4. The most suitable carbon and nitrogen sources were glucose and sodium nitrate, respectively. The sensitivity test of six fungicides to P. diospyri showed different degrees, the EC50 values of tebuconazole, azoxystrobin, chlorothalonil, difenoconazole, prochloraz, and carbendazim were 0.212, 0.313, 4.921, 0.552, 0.035 and 6.175 mu g/mL, respectively, revealing that P. diospyri was the most sensitive to prochloraz. In conclusion, P. diospyri grow fastest in acidic and well-lit environments, and prochloraz can be used as a protential fungicide for the treatment and prevention of the disease. This paper provides a theoretical basis for further research and field experiment.