Investigation of an epidemic of balsam poplar leaf blotch miner, Phyllonoricter Nipigon, (Leptidoptera: Gracilleriidae) in Thunder Bay, Ontario

Abstract

In the summer of 2018, an outbreak of Phylonorycter nipigon, commonly known as the balsam poplar leaf blotch miner, was identified on the Lakehead University campus in Thunder Bay, Ontario. All balsam poplar and trembling aspen trees in the study area were affected. Leaf blotch mines created by the larvae of this species were present on nearly 100% of leaves, thereby prompting this study. This study investigated leaf blotch mine counts and frequency distributions, leaf surface areas and two methods of measuring them. It was determined that leaf blotch mine frequency distributions follow a poisson-like pattern, and that a linear relationship exists between leaf surface area (cm2) and number of leaf blotch mines present on a leaf. Although balsam poplar has a significantly higher average leaf area (cm2) than trembling aspen, its leaves did not have a significantly larger average number of leaf blotch mines.