Evaluation Of Pine Wilt Disease Harm Degree And Studies On The Early-Warning To Calamity Of Monochamus Alternatus Hope In Ji’an Of Jiangxi Province

Pine wilt disease was a devastating destruction to native masson pine forest. Since it was discovered for the first time at the Jizhou district of Ji’an city in 2006,to 2013 the country or district of Ji’an with pine wilt disease occurred amounted to three,accounting for 23.08% of the total countries or districts in Ji’an city. The tendency that the disease spread in Ji’an city threatenend the forest resources seriously of Ji’an.And once the disease occurred in the Jinggangshan scenic spot,the loss would beyond measure.This thesis achieved the following research results through the evaluation of the damage degree of pine wilt disease and the study on the Early-Warning to Calamity of Monochamus alternatus Hope.Qualitative and quantitative research of pine wilt disease of Ji’an showed that:the damage degree was 2.44 between 2.0 to 2.5,indicating that the pine wilt disease was high hazard at Ji’an corresponding with the actual situation.Among the influential factors which lead to the result, the contribution of climate conditions was the largest.Low rainfall and the annual average temperature around 19℃ was very suitable/advantageous to the breeding of Bursaphelenchus xylophilus and the spread of M.alternatus Hope.Accordingly the prevention and control of pine wilt disease and the monitoring of population of M.alternatus Hope should be strengthened.In order to investigate the relationship between environment and the occurrence degree of M.alternatus Hope in the woods,1 stand factors were analyzed by using the method of principal component analysis,founding that the largest contribution to the occurrence of M.alternatus respectively are canopy density 、ground cover coverage rate、average breast diameter、canopy、altitude.And the canopy density 、ground cover coverage rate、average breast diameter had a significant effect on the population of M.alternatus with negative correlation through the partial correlation analysis between the 11 stand factor and the population of M.alternatus.On the basis of that the population of M.alternatus had correlation relationship with canopy density 、ground cover coverage rate、average breast diameter, multivariate regression model was established and the model reached significant level.The spatial distribution pattern of Monochamus alternatus Hope was determined by applying aggregated indices method,the results showed that the distribution pattern of M. alernatus larvae in Pinus massoniana was aggregated distribution. The difference of occurrence degree of M. alternatus among the various areas in Ji’an city was revealed by Using Arc GIS spatial analysis techniques, and the occurrence trends of M. alternatus were that there were much higher population density of M. alternatus in north and middle areas than in south, and from there M. Alternatus spread to surrounding areas in Ji’an city. The data of M. Alternatus individual numbers in Pinus massoniana collected from eight counties in Ji’an city were calculated by Using SPSS 17. 0 statistic software, and the two prediction models on the adult and larvae numbers of M. Alternatus were built respectively.By analyzing the risk of calamity of M.alternatus Hope, the framework and contents of the early-warning indexes system to Calamity of M. alternatus had established based on the different risky factors related to the risky source and he index weight values were set, the early-warning model was constructed. Using the occurrence data of M. alternatus in Jizhou district of Ji’an city in 2014 as an example, the risky degree was assessed, and the integrated early-warning values was: Y=88.8. The risky degree of Calamity of M. alternatus was third degree or severe risk degree.