中华松针蚧对云南松高生长的影响

云南松受中华松针蚧危害,当针叶虫口密度≤3只/束时,高生长量无损失;当针叶虫口密度>3只/束时,随着虫口密度的增大,高生长量损失逐渐增大;在同一虫口密度下,立地条件好的云南松受害后,其高生长损失大;据不同立地条件、不同虫口密度水平下云南松高生长损失大小,将发生中华松针蚧林分的林木分为健康、轻、中、重、特别严重5个等级.

Influence by Matsucoccus sinensis upon Height Growth of Pinus yunnanensis

Observation was conducted to analyze influence of Matsucoccus sinensis Chen. upon the height growth of Pinus yunnanensis. It was showed by the results that the height growth was not influenced when the population density of Matsucoccus sinensis Chen. was under 5 heads per bundle of needles. The height growth was reduced when there were more than 5 heads of pests per bundle of needle leaves, and the reduction quantity increased when the pest population increased above the density, and the loss of height growth of Pinus yunnanensis differed significantly from site conditions and the pest densities. The infection severity of Pinus yunnanensis stands by the Matsucoccus sinensis Chen. pest was classified into 4 categories i.e., healthy, slightly, intermediately and heavily infected based on statistical analysis.