Answer: Yellow jacket wasps are beneficial because they pollinate plants and feed on many pest insects such as flies and caterpillars. Late in the summer, however, their diet changes and they are strongly attracted to sugars. If the nest is out of the way, you can leave it alone because they all die over the winter, except the queen. The queen overwinters elsewhere and never returns. If you need to treat now, use a bee and wasp insect spray. Spray late in the day when the yellow jackets are there, quiet, and visibility is still good. For more information, see our website.
Photo courtesy of Jeff Trei, Flickr