Research on the spatial distribution patterns of Tomicus sp. in Pinus yunnanensis during the shoot feeding period
Author of the article:YU Lin-Feng1** HUANG Hua-Guo1 ZE Sang-Zi2 REN Li-Li1 ZONG Shi-Xiang1 LU Wen-Juan3 LUO You-Qin
Author's Workplace：1. Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing 100083, China; 2. Bureau of Harmful Forest Pest Management of Yunnan Province, Kunming 650000, China; 3. Xiangyun Forestry Bureau, Xiangyun 672100, China
Key Words：geostatistics, Tomicus yunnanensis, Tomicus minor, aggregate distribution
Abstract： [Objectives] Pinus yunnanensis, which is generally regarded as a key species for the conservation of soil and water in southwest China, is heavily damaged by Tomicus yunnanensis and Tomicus minor in pine forests in Xiangyun county, Yunnan province. The characteristic damage caused by these pests during the shoot feeding period was studied in order to provide guidance and suggestions for their monitoring and prevention.[Methods] The spatial distribution of T. yunnanensis and T. minor were analyzed using geostatistical methods in three forests with different levels of damage. [Results] Damage levels caused by these species differed significantly among the three forests; only 11.38% of shoots were damaged in lightly infested forest, 36.56% of shoots were damaged in moderately infested forest, and 59.70% of shoots were damaged in severely infested forest. An isotropic variogram indicated that T. yunnanensis and T. minor have an aggregated distribution in the three forests. The level of spatial dependence in the three forests could be ranked as follows: lightly infested forest > moderately infested forest>severely infested forest, and the intensity of local spatial continuity could be ranked as follows: lightly infested forest > moderately infested forest> severely infested forest. [Conclusion] Both T. yunnanensis and T. minor have aggregated distributions during the shoot feeding period. The damage to shoots caused by these aggregations can weaken Yunnan pine making it more conducive for adults to bore into the trunk and to reproduce. This study contributes to understanding the mechanism through which T. yunnanensis and T. minor damage pine trees, and provides technical guidance for their monitoring and control.