柳筒天牛幼虫为害特性与空间格局研究

柳筒天牛是为害沙柳根茎部的一种钻蛀性害虫,严重影响沙柳的生长。本文应用地统计学的方法分析了柳筒天牛幼虫的为害特性和空间格局。通过调查分析可知:柳筒天牛幼虫在单一蛀道内为害沙柳,其为害主要集中在沙柳基部,蛀道分布在地面以上10cm处至地面以下5cm处。柳筒天牛幼虫主要为害地径0.7~1.0cm的沙柳,且多分布在沙丘底部和迎风沙丘。分析沙丘顶部和沙丘底部2块样地柳筒天牛幼虫的数量可知,柳筒天牛在沙丘底部为害率要高于沙丘顶部,幼虫虫口密度分别达到(2.53±0.27)头/丛和(1.84±0.20)头/丛,且差异显著。柳筒天牛幼虫在沙丘顶部呈现聚集分布,在沙丘底部呈现随机分布。不同立地条件下的空间分布类型差异较为明显,但在两块样地内都呈现在某一特定区域内呈现大量聚集的现象。

Damage characteristics and spatial distribution of Oberea oculata larvae

Oberea oculata is a boring pest of Salix gordejevii roots, which seriously affects the growth of S. gordejevii. This study analyzed the damage characteristics and spatial distribution of O. oculata by using geostatistics method. Based on data analysis, O. oculata larvae focused on the base of S. gordejevii in a single tunnel, and the tunnels were distributed 10 cm above the ground and 5 cm underground. The damaged S.gordejevii diameter at ground was mainly 0.7-1.0 cm, which distributed at the bottom and top of the dune. By analyzing the quantity of O.oculata larvae in two woodlands, the damage percentage of S. gordejevii at the bottom of the dune was higher than at the top of the dune, and the O. oculata larval numbers at the bottom and top of the dune were (2.53±0.27) and 1.84±0.20) individuals per crowd, respectively, which was significantly different. O. oculata larvae at the top of the dune were aggregated distribution, while were random distribution at the bottom of the dune. Under different site conditions, the difference of spatial distribution in the two woodlands was obvious, but the aggregation points were observed in particular areas in the two woodlands.