Spatial Distribution of Ambrosia-Beetle Catches: A Possibly Useful Knowledge to Improve Mass-Trapping

Several species of ambrosia beetles (Coleoptera: Scolytidae) have recently started attacking standing, living beeches (Fagus sylvatica) in southern Belgium. In 2001, 1.3 million m³ of apparently healthy trees were struck. So far the outbreak has been limited to the Ardenne, and partly the Gaume, areas, and Brussels has been untouched. The city of Brussels is surrounded by a vast 4300 ha forest, mainly planted with beech, the Forêt de Soignes, of invaluable ecological and recreational value, of which 1600 ha belong to the regional authorities. In the spring 2001, these latter commissionned a study to assess the new threat to the forest. A 500 m×500 m grid of small traps, baited with ethanol and lineatin, was deployed over the regional part of the forest. The main species caught were Trypodendron domesticum, Anisandrus dispar and, in high numbers, Xylosandrus germanus, an exotic species of Asian origin found for the first time in Belgium in 1994. Whilst there was a consistent homogeneity between catches within the same sites (2 traps/site, distant by 2–6 m), there were no spatial relationships between catches at larger distances for T. domesticum and A. dispar. For X. germanus, spatial autocorrelations were observed within distances of 2000 m, suggesting that this species has sufficient mobility to cover this range. The planning of the 2002 trapping campaign will take this information into account: the traps will be deployed within a smaller grid.     

新型信息素诱剂对新疆梨园蛾类害虫的诱捕效果评价

利用性诱剂干扰交配或诱杀钻蛀性蛾类害虫是果园害虫生物防治的重要途径之一,研发既诱雄蛾也诱雌蛾的新型诱剂近年来颇受关注。本研究在苹果蠹蛾性信息素基础上,加入寄主植物挥发物--梨酯、苯乙酮、香叶醇、冬青油和苯乙醇等制成若干配方,在南疆两地(库尔勒与阿克苏地区)梨园中于蛾类害虫发生的早期和中期进行诱捕试验。对苹果蠹蛾诱集结果表明,虽然与仅含性信息素配方相比,添加植物挥发物的配方可诱集到雌蛾,但诱集虫量较少。对梨小食心虫的诱集结果表明,在库尔勒,大部分配方诱到的虫量多于商品诱剂(对照),其中,在性信息素中添加少量植物挥发性物质的配方诱集的虫量总体较多;在阿克苏,所有配方诱集的虫量均多于对照,在性信息素中是否添加植物挥发物质对诱集效果总体上没有影响。对优斑螟的诱集结果表明,仅含2种性信息素物质的配方诱集的虫量最大,与加入少量梨脂的配方接近。果园诱集试验结果说明,在苹果蠹蛾性信息素中添加梨脂等多种寄主植物挥发物的供试配方诱集雌蛾效果不理想,但对多种混合发生的夜蛾害虫雄性具有较好诱集效果。     

杨干透翅蛾性信息素的研究

研究表明我国西北、华北地区危害杨树主干的透翅蛾是杨干透翅蛾Sesia siningensis(Hsu)。经室内EAG测试,林间诱蛾和活雌蛾腺体提取及化学分析,证明顺3,顺13—十八碳二烯醇是其性信息素。利用人工合成的性信息素,在山西、甘肃等省连续4年大面积应用,证明可用来检测成虫羽化期和发生量、分布范围,并可降低雌蛾交配率28.1％～98.5％,平均降低42.8％～47.6％;连续3年诱蛾后,虫口密度降低38.2％。