Cottonwood Leaf Beetle

I was so happy that we found a number of these tiny beetles at the end of our wet day, out at Bow Valley Provincial Park, on 18 June 2013. After a long, rather fast-paced hike in the rain around the two lakes and then back to the cars, we drove down to the river and, as the rain had finally stopped, went for just a short, slow walk along the trail through the woods.

"Cottonwoods (which are Poplars) are host to quite an array of destructive insect herbivores, ten species are well known, and some can reach population densities of pest proportions. The most damaging are defoliators and wood borers, each exhibiting characteristic damage on particular parts of the trees. The former cause loss of vigor and the latter reduce lumber quality. Important defoliating insects are the cottonwood leaf beetle (Chrysomela scripta), cottonwood dagger moth (Acronicta lepusculina), forest tent caterpillar (Malacosoma disstria), poplar leaffolding sawfly (Phyllocolpa bozemani), fall cankerworm (Alsophila pometaria), tentmaker (Ichthyura maimbachiana) and the fall webworm (Hyphantria cunea).

Borers include the poplar borer (Saperda calcarata), cottonwood borer (Plectrodera scalator), flatheaded wood borer (Dicerca divaricata), carpenterworm (Prionoxystus robiniae), poplar-and-willow borer (Cryptorhynchus lapathi), clearwing borers (Paranthrene spp.) and the bronze poplar borer (Agrilus liragus). Several mites and aphids infest cottonwood, but not often with fatal effects."

www.isaontario.com/content/confusing-cottonwoods