Abstract:

In order to study the technology of meteorological forecasting and warning of Valsa sordida Nits in northeast China, the meteorological suitability forecasting model of Valsa sordida Nits for northeast China was established. The methods of correlation analysis, stepwise regression and stepwise differentiation were used in establishing model based on the data for occurrence degree caused by Valsa sordida Nits in northeast China from 2002 to 2008 and the corresponding meteorological elements. Furthermore, the meteorological suitability index was divided into 4 grades of very suitable, suitable, basic suitable, not suitable, which could reflect the suitable degree of meteorological condition for occurrence and development of Valsa sordida Nits. The results showed that the occurring area of Valsa sordida Nits was positively correlated to the days of ≥15℃ of daily air temperature range in winter, average air temperature in spring and early summer. It was favorable to the development of Valsa sordida Nits as daily air temperature range in winter, air temperature in spring and early summer increased. The conditions of freezing injury in winter, temperature and air humidity in spring were the main impacting factors to the occurrence and development of Valsa sordida Nits, air temperature and humidity were mostly related to the occurring area of Valsa sordida Nits. The key meteorological factors which affected the occurrence and development of Valsa sordida Nits in northeast China were wind speed in late March, air relative humidity in March, temperature-humidity coefficient in April, the air temperature in March and May, and also early and last April, the days of ≥15℃ of daily air temperature range from November to December. The forecasting model of meteorological suitability fitted well with the historical data of 2002-2008 and gave good results with forecasting accuracy above 75% for northeast China and for 3 provinces respectively with the order of Heilongjiang>Jilin>Liaoning, when used in disease trial forecast in 2009 with high occurring area.