Abstract: The relationships between Valsa sordida nits and meteorological conditions were analyzed in order to provide the scientific references for forecasting and controlling the disease. Based on the observational data of Valsa sordida nits and the meteorological data at 14 representative stations from 2002 to 2008, their relationships were discussed by a correlation analysis method. The results indicate that the incidence rates of Valsa sordida nits is in a positive correlation with some meteorological conditions such as air temperature during October of previous  year to April of current year, the temperature-humidity coefficient from May to September, precipitation, the number of precipitation days, the relative humidity from October of previous year to March of current year, the extreme maximum temperature, the diurnal temperature range (DTR), duration of large DTR and the mean wind speed, while it is in a negative correlation with the temperature-humidity coefficient during October of  previous year to April of current year, the mean temperature from May to September, the relative humidity from December of previous year to January of current year, the extreme minimum temperature and sunshine duration. Some climatic conditions such as humidity, warming, cold and the sudden change of cold and warm in winter could strengthen the occurrence and development of Valsa sordida nits, while some others such as abundance sunshine and high summer temperature could restrain the disease.

Key words: Heilongjiang province, Valsa sordida nits, Meteorological factor, Correlation analysis