Mystery Plant

I put this one out there for any and all to try and identify. I found this mystery plant growing in my "field" two days ago, and I don't know what it is. I've tried keying it out using Newcomb's Wildflower Guide (which until now has never failed me), and I even tried to find a matching photo in the Audubon wildflower field guide, but to no avail.



So, here is a photo of the flower head (there were/are two, each on its own stalk), and one of a leaf (note how it wraps around the stem).




The insects on the flower are rose chafers, which arrived en force yesterday, much to my dismay, and are eating all the flowers on fruiting trees and shrubs, such as grapes and viburnums, as well as the leaves of apple trees, hops, et al. If anyone has a cure for these, please send it along, too. There are just too many for picking off (I've done that and filled entire mason jars in under an hour), and garlic spray doesn't seem to deter them any (plus, spraying the garlic when the plant is in bloom deters the bees, which means no pollination, and thus no fruit - might as well let the chafers eat the flowers as it will have the same result).