| Autor: |
Yuan, Fei, Luo, You-qing, Shi, Juan, Keliövaara, Kari, Qi, Guo-xin, Li, Xiang-jun, Han, Yong-shi, Chen, Chao |
| Zdroj: |
Forestry Studies in China; March 2008, Vol. 10 Issue: 1 p9-13, 5p |
| Abstrakt: |
After the outbreak of Dendrolimus superansButer in 2002, many insect borers quickly invaded larch (Larix gmeliniiRupr.) forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, collecting adults in iron traps and measuring areas of galleries to study the invasive sequence, their ecological niche and the extent of the different effects by the main insect borers to their hosts. The results showed that the damage of D. superansweakened L. gmelinii, first Ips subelongatusMotschulsky invaded, followed by Acanthocinus carinulatusGebler, Monochamus urussoviFisher and M. sutorL. After the outbreak of D. superans, the average density of longhorn beetles per L. gmeliniitree increased. The ecological niche of Ips subelongatusstretches almost from the base to the top of the trunk. The number of insects in older stands of L. gmeliniiis larger than those in middle aged stands. They do not damage healthy trees of L. gmelinii. The ecological niche of A. carinulatusis higher in dead L. gmeliniitrees than in weak ones. The degree of damage is directly proportional with age and depth of bark. M. urussovimainly damages trunks below 4 m in weak trees; in dead trees they can do damage up to 6 m in height. M. sutormainly damages trunks below 5 m in weak L. gmeliniitrees; in dead trees they cause damage up to 7 m. Again, the degree of damage is directly proportional with age. None of the three species of longhorn beetles damage healthy L. gmeliniiand younger trees. Among the main insect borers, the degree of damage caused by I. subelongatusis more serious than that of other insects.After the outbreak of Dendrolimus superansButer in 2002, many insect borers quickly invaded larch (Larix gmeliniiRupr.) forests in the Aershan of Inner Mongolia. Methods involved included setting sample plots, collecting adults in iron traps and measuring areas of galleries to study the invasive sequence, their ecological niche and the extent of the different effects by the main insect borers to their hosts. The results showed that the damage of D. superansweakened L. gmelinii, first Ips subelongatusMotschulsky invaded, followed by Acanthocinus carinulatusGebler, Monochamus urussoviFisher and M. sutorL. After the outbreak of D. superans, the average density of longhorn beetles per L. gmeliniitree increased. The ecological niche of Ips subelongatusstretches almost from the base to the top of the trunk. The number of insects in older stands of L. gmeliniiis larger than those in middle aged stands. They do not damage healthy trees of L. gmelinii. The ecological niche of A. carinulatusis higher in dead L. gmeliniitrees than in weak ones. The degree of damage is directly proportional with age and depth of bark. M. urussovimainly damages trunks below 4 m in weak trees; in dead trees they can do damage up to 6 m in height. M. sutormainly damages trunks below 5 m in weak L. gmeliniitrees; in dead trees they cause damage up to 7 m. Again, the degree of damage is directly proportional with age. None of the three species of longhorn beetles damage healthy L. gmeliniiand younger trees. Among the main insect borers, the degree of damage caused by I. subelongatusis more serious than that of other insects. |
| Databáze: |
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