Question: My wife keeps finding these large wasps around our house. She is allergic to bee stings so we have been looking for the source. I just found a gray papery nest but don't see the wasp. Do you think this is where they are coming from?
Answer: It is important to distinguish between the different types of stinging insects before implementing any control measures. Wasps, which include yellowjackets, hornets and other wasps, can be either solitary or social. Solitary wasps are usually non-aggressive and rarely defend their nests. The venom of a solitary wasp has anesthetic qualities and is rarely a problem for the gardener. However, social wasps such as yellowjackets, paper wasps and hornets use their venom as a defensive weapon and often attack in large numbers when threatened. Their sting causes severe pain and can be very serious to someone that has allergic tendencies.
Wasps known as yellowjackets are true to their name, yellow and black, except for one notable exception, the bald-faced hornet yellowjacket which has white and black markings. From your description your wasp is most likely the bald-faced hornet. Although it is called a hornet it is an aerial yellowjacket, one of seven species in North America. There is only one hornet in North America and that is an introduced species from Europe, the European hornet. This hornet, similar in size, is commonly mistaken for the bald-faced hornet but can be correctly identified by its yellow and black coloring rather than white and black.
Nests are helpful when trying to identify the type of social wasp. Paper wasp nests are located in open areas and have a honeycomb of larval cells that are oriented downward. The bald-faced hornet's nest is usually very large, pear shaped with a round entrance hole at the bottom. These nests are located in shrubbery or sometimes under the eaves of buildings. Common yellowjackets build their nests underground most of the time. Entrance holes may be in lawns, garden beds or fields. The European hornet's nest is found in cavities such as a hollow tree somewhere approximately 6 feet off the ground.
Bald-faced hornets can be considered beneficial as they reduce unwanted insects including other common yellowjackets. If nests are not located within 10 ten feet of the house they can be ignored. If someone has a known allergy to wasps the nests should be removed by a professional pest management person. If a person is willing to try to remove a nest, a wasp and hornet insecticide should be sprayed directly into the nest opening at night. Holding the nozzle against the opening will prevent any wasps from escaping. Protective garments and goggles are recommended.
Mona Bawgus is a certified master gardener and consumer horticulturist with Rutgers Cooperative Extension of Atlantic County. Write to her c/o Rutgers Cooperative Extension, 6260 Old Harding Highway, Mays Landing, NJ 08330. Email: