Tree species effects on Btk control of spruce budworm

云杉芽虫是北美东部最具破坏性的森林害虫，目前正在爆发，魁北克的严重落叶蔓延到新玩法。目前控制云杉芽虫的努力包括喷洒新型生物杀虫剂，与过去用于防治疫情的化学制剂相比，这种杀虫剂大大降低了非目标毒性。然而，我们仍在学习如何有效地使用这些代理。我们将致力于了解一种生物杀虫剂Btk对NB和魁北克北方云杉芽虫的两种主要宿主树木：香脂冷杉和黑云杉的相对有效性。Btk喷雾剂停留在树叶上，在那里它被喂养的芽虫幼虫摄取。由于这两棵树的分支和针叶结构不同，而且作为发育中幼虫食物的质量也不同，Btk可能被摄取，并且可能对每棵树上取食的芽虫产生不同的作用。我们将测量这两个树种的芽虫死亡率，并在不同的物种组成的林分，比较林分与Btk处理过的林分。这将使我们设计Btk应用策略，以有效地控制芽虫，在一个forestmosaic的可变物种组成，同时使用最少的杀虫剂。

Spruce budworm is the most damaging forest pest in eastern North America, and is currently undergoing anoutbreak, with severe defoliation in Quebec spreading into New Brunswick. Current efforts to control sprucebudworm involve spraying with novel biological insecticides, which (compared with chemical agents usedagainst past outbreaks) have enormously reduced non-target toxicity. However, we are still learning how to usethese agents effectively and efficiently. We will work to understand the relative effectiveness of one biologicalinsecticide, Btk, on the two major host trees of spruce budworm in northern NB and Quebec: balsam fir andblack spruce. Btk spray settles on tree foliage, where it is ingested by feeding budworm larvae. Because thetwo trees differ in branch and needle architecture, and also in quality as food for developing larvae, Btk may beingested, and may work, differently on budworm feeding on each tree. We will measure budworm mortality onthe two tree species, and in forest stands differing in species composition, comparing stands treated with Btk tountreated stands. This will let us design Btk application strategies to control budworm effectively, in a forestmosaic of variable species composition, while using a minimum of insecticide.