Introduced Phragmites ( Phragmites australis ssp. australis ) forms part of an invasion assemblage in North America that includes non-native insect herbivores and parasitoids, some of which are now found on both the introduced and native subspecies of Phragmites ( P. australis ssp. americanus ). This insect assemblage is key to understanding the impact of P. australis invasion and interpreting the efficacy of biological control used against introduced P. australis . Our study provides the first dedicated comparison of insect assemblages associated with native and introduced P. australis in Canada. From a 2016 to 2017 survey of 28 geographically paired sites across Ontario, Canada, fourteen insect taxa were recorded from both subspecies. Genotype had no effect on α-diversity but stem attack rates from at least one herbivore were higher on native populations than on paired introduced populations (+ 18.6%). We report the first record of Chaetococcus phragmitis (Homoptera: Pseudococcidae) and Rhizedra lutosa (Lepidoptera: Noctuidae) in Canada and of R. lutosa and Lasioptera hungarica (Diptera: Cecidomyiidae) on native P. australis in North America.