In the summer of 2008 I was working as a field botanist for the UMass Landscape Ecology Lab, identifying all the plants in wetland plots throughout Massachusetts. I kept coming across distinctive little waxy tufts on the undersides of arrowwood (Viburnum dentatum) leaves.
When I removed one and examined it, I saw that the white filaments were emanating from a featureless, flat, yellow oval. I couldn’t think of anything it could be other than a whitefly nymph, and I ended up including a picture of it in the “white fluff” section of Tracks & Sign of Insects (p. 173). The next summer, when I started seeing these waxy tufts again, I decided to collect some just to be sure. I stuffed a leaf with several of these things on it into a vial, took it home, and a couple of weeks later there were some adult whiteflies in the vial. I was glad not to have to make a last-minute change as the book was heading to the printers.
I have a habit of not throwing things away, and last month when I was getting some things together to send to the USDA Systematic Entomology Lab for identification, I found the dry, crinkled arrowwood leaf with the whiteflies’ wax-covered nymphal exuviae still stuck to it, and I decided to send it along just for the heck of it. I knew this was far from proper technique for preserving whiteflies, but I also knew that whitefly classification is based on the nymphs (the adults all look pretty much the same, for the most part), and I figured that the shed skins would retain whatever characters were needed. Today I got an email notification that Gregory A. Evans had identified the specimens as Trialeurodes pergandei. Armed with this name and Google, I found Dr. Evans’ Host Plant List of the Whiteflies (Aleyrodidae) of the World, and I learned that this species feeds on a number of unrelated plants, but happens to be the only whitefly that is known to feed on arrowwood.
How nice to have a free government service that tells us what our bugs are.