I believe the word is entomologist. No idea about the aphid infestation, I haven't noticed any in central Calgary, although the annual maple-beetle infestation is beginning and it looks like there's gonna be a lot of them this year.
edit: just doing a bit of research, the insects we're infested with are not maple-beetles, although we've always called them that. They're actually boxelder bugs. Anybody else get these? They live in the trees in our front yard, and every autumn they invade our porch and try to get into the house at every opportunity.
http://www.extension.umn.edu/distrib...re/DG0998.html