东江林场20个乡土阔叶树种拟木蠹蛾为害调查

拟木蠹蛾Arbela spp.是华南地区严重影响人工林质量和稳定性的一类钻蛀害虫。本研究以广东省东江林场20个乡土阔叶树种人工幼林为研究对象,调查分析拟木蠹蛾对不同树种的为害状况及其与林木生长的关系。结果表明:7 a生时共有5个树种受到拟木蠹蛾为害,分别为西南桦Betula alnoides、海南红豆Ormosia pinnata、山杜英Elaeocarpus sylvestris、翻白叶Potentilla fulgens和楝叶吴茱萸Evodia glabrifolia,8 a生时新增1个受害树种——秋枫Bischofia javanica;受害树种生长表现和感虫情况均差异显著(P0.05),但种内感虫个体生长表现与未感虫个体差异不显著(P0.05);这些受害树种的虫口高度分布范围不同,生长较快的翻白叶和西南桦,其虫口主要分布在树冠以下,生长速度中等的海南红豆和山杜英的虫口分别集中在树冠下缘附近和树冠下缘上部,生长较慢的楝叶吴茱萸和秋枫的虫口则分别多在树冠下缘附近及其下部和树冠下缘及其上部,据此初步提出以枝下高作为主要参考指标分析其虫口高度分布特征。研究结果补充完善了拟木蠹蛾发生规律和为害特征方面的资料,且为该区域营建混交林的树种选择提供参考。

Investigation on attack of Arbela spp. to 20 indigenous broad-leaved tree species in Dongjiang Forest Farm,Guangdong Province

Arbela spp. is a kind of trunk borer influencing severely plantation quality and stability in South China. Attacks of Arbela spp. in young plantation of 20 indigenous broad-leaved tree species were investigated, and relationship between damage and tree growth were analyzed in Dongjiang State Forest Farm, Guangdong Province. The results showed that 5 tree species including Betula alnoidas, Ormosia pinnata, Elaeocarpus sylvestris, Potentilla fulgens, Evodia glabrifolia, were damaged by Arbela spp. when 7 years old, while one more species, Bischofia javanica was damaged when 8 years old. There were significant differences of growth performance ( P < 0. 05 ) among these 6 tree species, while growth performance did not differ remarkably between damaged and non-damaged individuals ( P> 0. 05 ) . Height distribution of borer attacks were different among these tree species, borer attacks mostly occurred under crown for fast-growing tree species such as B. alnoidas and P. fulgens;the borer concentrated in the lower edge of canopy for medium-growing tree species like O. pinnata; and the borers occurred in upper part of the lower canopy edge for E. sylvestris, and under or in upper part of the lower canopy edge for two slow-growing tree species E. glabrifolia and B. javanica respectively. Therefore, height under branch could be the main reference index to analyze borer height distribution on tree. The results complement the information about Arbela spp. occurrence and damage characteristic, and provide some evidences for tree species selection in establishment of mixed plantation.