Field notes about yellowjackets
By Chris Williams on March 8, 2019.
The past ‘pest’ season (2018) seemed to be another banner year for yellowjackets. Ground nesting species and those that seem to prefer to nest within buildings were very troublesome from late summer right up until November in my territory. Wait- there are different species of yellowjackets? Actually, there are dozens of species of yellowjackets in North America and most are content to live deep within forested wilderness so only a relative handful are considered serious pests. I’m not quite sure why it took me 30 years to ask myself this question, but the entomologist in me decided to find out which ones are here in Northern New England.
The yellowjacket species, (Vespula sp.) I came across on service visits this past summer into fall, (not claiming that these are the only ones here, just my experience) were the Eastern, Common, German, Aerial, and the Bald-faced Hornet. The latter two species are in the sub genus Dolichovespula and for the most part make an aerial nest in trees, shrubs, eaves of homes and occasionally will build quite close to the ground. The aerial yellowjacket (Dolichovespula arenaria) is the first species I encountered quite early in the summer as some very unwelcomed guests beneath a customer’s pool deck, and it’s probably the species that got me the previous summer while I was staining my deck! During August and September were the first calls for Bald-faced Hornets (Dolichovespula maculata). Though the name would suggest it’s a different type of wasp, it is in fact one of a couple species of black and white ‘yellow jacket’ and it is an impressive wasp. Mature nests can be quite large and built from sturdy greyish brown paper. The nests are always exposed and fortunately easy to treat, though getting pelted on the head by attacking wasps is a bit unnerving!
Speaking of unnerving, nothing can top waking up in your bedroom and finding that a previously unknown colony of yellowjackets have chewed through your ceiling and now hundreds are flying around the living space. I had several service calls like this in August and while I was expecting the culprit to be the German yellowjacket (Vespula germanica) all of them involved the common yellow jacket (Vespula vulgaris). After a while, I was starting to wonder if I was going to have any encounters with the German yellowjacket, but virtually all of the late season calls for void nesting yellow jackets through September and October involved this invasive species. This is a very troublesome wasp with very large colonies and they were everywhere! I’ll admit I was so happy for late fall. I was so tired of dealing with them. And finally, the ground nesting yellow jacket service calls all involved the Eastern yellowjacket, (Vespula maculifrons). There you have it!
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