(Horticulture) Pheromone of Apple Sawfly: New Tool for Management of a Re-emerging Pest

苹果叶蜂Hoplocampa teStudina是危害苹果树的主要害虫。成虫在春天从土壤中出来交配。雌性被苹果花和产卵所吸引。一旦幼虫孵化，它们就会沿着幼果的表面觅食，造成丝带状的疤痕，从而降低水果的质量。如果幼虫进入果实，他们会在每串苹果中挖出3-4个果实，形成粘稠的棕色果皮，使果实掉落或滞销。在未喷洒或有机果园中，苹果叶蜂可能导致高达90%的作物损失；即使在较低的损害水平，分拣滞销水果的成本对种植者来说也是一种损失。有机种植者没有有效的方法来控制苹果叶蜂，只能去除被感染的枝条，这是高度劳动密集型的，仍然会导致产量损失。在传统果园中，苹果叶蜂以前曾被用广谱杀虫剂防治其他害虫。其中大部分现在已经被撤回，即使在喷洒了苹果的果园里，苹果叶蜂也再次成为一个问题。此外，应避免在开花期间喷洒杀虫剂，因为这可能会影响授粉昆虫，并扰乱种植者使用的综合病虫害管理计划。雌性木蝇利用长程性信息素吸引雄性。如果能够鉴定和合成苹果叶蜂性信息素各组分的化学结构，将有助于减轻苹果叶蜂性信息素的危害。以信息素为诱饵的诱捕器可用于检测苹果叶蜂的存在，并可更有效地应用控制方法。信息素还可以用来通过大量诱捕和交配中断等方法来控制苹果叶蜂。这些方法已经被用来对付其他已经识别出信息素的害虫。信息素是无毒的天然产物，专门针对目标害虫，对其他动植物没有影响，而且活性很小。项目合作伙伴此前曾试图识别苹果叶蜂性信息素，但由于难以获得足够的活昆虫进行这项工作，一直未获成功。苹果叶蜂一年只发生一代，目前还没有已知的实验室培养方法。这个简短的项目将把学术和商业合作伙伴聚集在一起，共同努力克服这一限制。种植者合作伙伴的知识和设施将被用来定位以前感染苹果叶蜂的果园。学术和商业合作伙伴将共同努力，开发从土壤中分离幼虫和蛹的方法，然后收集和处理更大的土壤样本。幼虫和蛹将被饲养到成虫，并开始信息素鉴定过程。这不太可能在该项目内完全完成，但结果将为鉴定信息素并开发其在未来项目中对苹果叶蜂的管理提供坚实的基础。该项目的学术合作伙伴是格林威治大学自然资源研究所，该研究所在昆虫信息素的识别和应用方面具有50多年的经验，以及英国领先的水果研究机构NIAB East Mling。商业合作伙伴是已经生产和销售150多种昆虫信息素的Russell IPM，定期为英国种植者提供病虫害控制建议的两个农业组织Avalon Ltd和Agrovista，以及两个经历过苹果锯蝇严重损害的有机苹果种植者Mole End和Rudford Farm。我们还得到了Delphy和PCFruit的支持，这两家公司分别是荷兰和比利时领先的水果研发组织，它们热衷于寻找新的解决方案来管理苹果叶蜂。

Apple sawfly, Hoplocampa testudinea, is a damaging pest of commercial apple trees. Adults emerge from the soil in spring and mate. Females are attracted to apple blossoms and lay eggs. Once the larvae hatch, they feed along the surface of young fruits causing ribbon-like scars which downgrade fruit. If the larvae enter the fruit, they tunnel in 3-4 fruits per apple cluster creating a sticky brown frass, making fruits drop or be unmarketable. In unsprayed or organic orchards apple sawfly can cause up to 90% crop loss; even at lower damage levels the costs of sorting the unmarketable fruit are a loss to the grower. Organic growers have no effective means for controlling apple sawfly other than removing infested shoots which is highly labour-intensive and still results in yield loss. In conventional orchards, apple sawfly has previously been controlled using broad-spectrum insecticides against other pests. The majority of these have now been withdrawn and apple sawfly is re-emerging as a problem even in sprayed orchards. Furthermore, spraying during flowering is to be avoided as this may impact pollinating insects and disrupt integrated pest and disease management programmes used by growers.Female sawflies attract males using long-range sex pheromones. If the chemical structures of the components of the sex pheromone of apple sawfly could be identified and synthesised, these could be used to help reduce the damage caused by this pest. Traps baited with the pheromone can be used to detect the presence of apple sawfly and apply control methods more efficiently. The pheromone might also be used to control apple sawfly by approaches such as mass trapping and mating disruption. These approaches have been used against other insect pests where the pheromone has been identified. The pheromones are non-toxic natural products, specific for the target pest and without effect on other animals and plants, and they are active in very small amounts.The project partners have previously attempted to identify the sex pheromone of apple sawfly, but have been unsuccessful due to difficulties in obtaining sufficient live insects for the work. Apple sawfly has only one generation per year and there are no known methods for laboratory culture. This short project will bring together academic and commercial partners in a concerted attempt to overcome this constraint. The knowledge and facilities of the grower partners will be used to locate orchards previously infested with apple sawfly. The academic and commercial partners will work together to develop methods for isolation of larvae and pupae from the soil and then will collect and process larger soil samples. The larvae and pupae will be reared through to adults and the process of pheromone identification will be started. It is unlikely that this will be fully completed within this project, but the results will provide a firm basis for identification of the pheromone and development of its use for management of apple sawfly in future projects. The opportunity will also be taken to set up a network of traps for monitoring adult sawfly and assess the damage caused, providing new data on the distribution and phenology of this pest.Academic partners in this project are the Natural Resources Institute, University of Greenwich, which has over 50 years of experience in identification and application of insect pheromones, and NIAB East Malling, the leading UK fruit research institute. Commercial partners are Russell IPM who already produce and sell more than 150 insect pheromones, Avalon Ltd and Agrovista, two agronomy groups who regularly advise UK growers on pest control, and Mole End and Rudford Farms, two organic apple growers who experience significant apple sawfly damage. We also have support from Delphy and PCFruit, leading fruit research and development organisations in The Netherlands and Belgium, respectively, which are keen to find new solutions to managing apple sawfly.