High rates of parasitism of blueberry spanworm (Lepidoptera: Geometridae) by Ichneumonidae and Tachinidae in commercial lowbush blueberry fields

Blueberry spanworm, Itame (Macaria) argillacearia Packard, is an important defoliator of lowbush blueberry (Vaccinium angustifolium Aiton), a major crop in eastern Canada. In the summer of 2012, we collected a large number of blueberry spanworm larvae from two managed blueberry fields in Colchester Co., Nova Scotia. Approximately 50-60 % of the field-collected larvae maintained in the laboratory were parasitized and killed. Identifications of parasitoids were based on morphological characters and mitochondrial cytochrome oxidase I sequencing. The majority of parasitism was by Phryxe pecosensis (Diptera: Tachinidae), and a wasp suspected to be a new species of Tranosemella or Tranosema (Hymenoptera: Ichneumonidae). Our results demonstrate that parasitism of blueberry spanworm can be high in lowbush blueberry and that conservation or augmentative biological control should be considered in future development of management programs for this pest.