Occurrence And Sustainable Management Of Dendroctonus Valens

Red turpentine beetle(Dendroctonus valens LeCtone)is a kind of exotic pest to Northwest China in 1998, which distributed in North America originally and spreaded into China later.and it had brought heavily damage to Forest Ecosystem and economic loss of China. In order to research its occurrence and ecological characteristics, the writer chosed Malan Forest in Xunyi, Shaanxi and researched on temporal and spatial population dynamics, the flow-out pattern and the related relationships between red turpentine beetle and other environment factors and integrated management of it. The results are as follows:(1) In the respect of red turpentine beetle occurrence, the result shows that there is no obvious differences of the flow-out pattern under different altitude conditions,forest stand conditions and years, but the total numbers of the adult that flew out have more obvious relevance with forest stand condition. The variation trend of the adult flew out is:the adult begin to fly out the bark at early May, and reach the peak at the middle may, and then the number comes down. At early June, there is another peak which is weaker and lasts shorter than the first time. From then on the number of adult fly out keeps on a steady level.(2) The results shows that pitch tube of D. valens take the aggregation distribution in forest by the analysis of classic statistics such as Diffusion Coefficient C, David and Moore indictor, Cassie R M indictor, Iwao crowding index, coefficient of mean crowdiness-mean density and so on. And the writer also found that D. valens attacks the weak and attacked host individual firstly.(3) By the the research of the relevance between pines attacked ratio and pine DBH (diameter at breast height), height, mountain slope aspect and position, site conditions. The results show that the pines of 20~30cm DBH are the main attacked target. Pines lived in 1500m high also get the most serious damage. Pines lived on the tops of mountains are always damaged much more heavily than adretto, half-adretto, and opaco. Pines under the valley get more attacks than the pines on the middle and headpiece of mountain. Comparison during different site conditions shows that pines on the wayside which disturbed most by human activities suffered most attacks from D. valens,then is the forest edge part, and pines inside are damaged least comparatively.(4) The merit and demerit of sustainable management methods in practical applications of red turpentine beetle are comprehensively analyzed. The writer also analyzed the ecological theory and the procedure of the prevention and cure strategy of red turpentine beetle, which offers referable theoretical basis to northwest area of China.