| 摘要: |
| 【目的】研究桉树云斑天牛大尺度范围的危害特征，为进一步科学有效制定云斑天牛防控措施提供参考依据。【方法】2017年7-9月系统调查了重庆市19个区县102个桉树林云斑天牛危害样点，通过解剖受害树干系统分析云斑天牛的危害特征及其相关影响因素。在此基础上，利用主成分分析法研究桉树云斑天牛致灾的关键因素，并评估各调查点桉树云斑天牛危害的风险水平。【结果】重庆桉树林调查点云斑天牛轻度、中度及重度危害的受害株率分别为3.4%，15.8%和55.3%，平均值达到40.2%，为重度且成灾水平。危害特征分析结果表明，当年有效刻槽数（虫口密度）与无效刻槽数在云斑天牛重度危害下存在显著相关性（P<0.05）；无论是同一树高不同危害程度间还是同一危害程度不同树高间，当年株均无效刻槽数均有明显的规律变化，且出现了显著性差异（P<0.05）。当年虫口密度在轻度、中度及重度危害下均以树高区间≤1.0 m为主，且≤1.0 m显著多于3.1 m以上（P<0.05）；同一树高区间虫口密度均为重度危害显著大于轻度和中度危害（P<0.05），轻度和中度危害间差异不显著（P>0.05）。在轻度和中度危害下，受害株率与虫口密度的关系模型更适合用三次函数方程表示，但多数差异不显著（P>0.05）；在重度及总危害条件下，树高≤1.0 m及总高度上受害株率与虫口密度的关系可用幂函数表示，其他高度受害株率与虫口密度的关系符合三次函数关系，且多数差异显著（P<0.05）。相关性和主成分分析结果表明，受害株率与虫口密度均受到林分类型和桉树品种的极显著影响（P<0.01）。基于调查点各因素得分的PCA排序表明，无危害和轻度危害样点的生境条件及危害特征相似性高，重度危害则差异很大，而中度危害居于前2类中间，呈明显的过渡特征。铜梁、璧山、丰都、渝北、垫江、长寿和永川等区县具有高风险危害中心。【结论】重庆各调查样点桉树云斑天牛种群数量呈上升趋势，危害程度总体属于重度且成灾水平；不同危害程度下受害株率与虫口密度的关系可用三次函数或幂函数表示；重度危害下各样点桉树云斑天牛的危害特征与生境条件差异很大，林分类型和桉树品种是云斑天牛致灾的关键因素。 |
| 关键词: 云斑天牛 桉树 危害特征 主成分分析 重庆 |
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| 基金项目:重庆市科技局社会民生项目（cstc2017shms-xdny80070） |
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| Damage characteristics of Batocera lineolata in eucalypti plantations in a large scale |
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SUN Jiaqi,DONG Changping,TIAN Yan,et al
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| Abstract: |
| 【Objective】This study aims at analyzing damage characteristics of Batocera lineolata in eucalypti plantations of Chongqing to provide reference for effective control of pest population.【Method】Field investigations were conducted from July to September,2017 at 102 locations of eucalypti plantations in 19 counties of Chongqing and the basic conditions for damage of B.lineolata were analyzed.The critical factors influencing the damage differences of B. lineolata in different plantations were also studied by the principal component analysis (PCA).【Result】The damage caused by B.lineolata varied considerably in eucalypti plantations at all sampling points.In lightly,moderately and heavily infested plantations,3.4%,15.8% and 55.3% trees were infested with the average infestation of 40.2% in the level of heavy damage.The larvae mainly infested eucalypti trunks below 1.0 m and 1.1-2.0 m.In heavily infested plantations,the yearly effective notch groove showed a significant correlation with the ineffective one (P<0.05).The number of ineffective notch groove below 1.0 m and 1.1-2.0 m was higher than that 2.1-3.0 m and above 3.1 m for all damage levels,and significant differences were found in heavy degree (P<0.05).The individual number of larvae was significantly higher in trunks below 1.0 m than those above 3.1 m (P<0.05).For same height of trunk,there was no significant differences between slight and moderate damages (P>0.05),while the numbers of larvae in heavy damage were significantly greater than in slight and moderate damages (P<0.05).The regression analysis indicated that cubic function models were more suitable for the correlation between damage rate and population density of larvae in sampling plantations with slight and moderate damages without significant differences in most cases (P>0.05).For the sampling plantations with heavy and total damages,power function models were more suitable for the correlation in the total height or below 1.0 m.In contrast,cubic function models were more suitable for the correlation in other heights of trunks,and most models varied greatly in regression correlation (P<0.05).The effects of several environmental factors on damage rate and population density of larvae varied among all eucalypti plantations,and there were very significant effects in forest type and eucalypti variety (P<0.01).Forest type and eucalypti variety were the largest environmental factors affecting damage degree in different plantations.The principal component analysis (PCA) showed that greater difference existed in damage degree and environmental factors among different plantations and damage levels.Comprehensive values of principal components suggested that the similarity of habitat conditions and damage characteristics was the highest in the sampling plantations with no damage or slight damage,while significant difference was found in those with moderate damage and heavy damage.The areas with high risk included Tongliang,Bishan,Fengdu,Yubei,Dianjiang,Changshou and Yongchuan.【Conclusion】The damage of B.lineolata in the sampling eucalypti plantations of Chongqing reached heavy damage that can cause disasters.The correlation between damage rates and population density in different plantations can be described by power function or cubic function models,and forest type and eucalypti variety have key effects on the difference of damage rates and population density among sampling points. |
| Key words: Batocera lineolata eucalypti damage characteristics principal component analysis Chongqing |
