by Tris Hoffman, Flathead National Forest Weed Coordinator
silversagebrush@hotmail.com

Walt Disney got it wrong:  The bald-faced hornet

When Disney adapted A.A. Milne’s Winnie the Pooh into a cute animation, he made mistake.  If the “Bear of Very Little Brain” wanted honey, he should have looked for a large hollow tree. The illustrations in Milne’s original stories show Pooh climbing a large tree, but he is not going after the papery egg-shaped nest that the animated bear seems to obsess about.  Disney’s globular gray nest would never provide Pooh with honey, because that is a typical nest of a bald-faced hornet.

The bald-faced hornet is a social insect like the honeybee, but unlike the bee, it eats both nectar and other insects.  As a child I feared bald-faced hornets more than any other stinging insect because I they seemed so hostile.  Indeed, they would chase me all around the barn.  While it is true that bald-faced hornets are aggressive if you get in their space, what I didn’t realize is that horseflies and deerflies are their favorite food.  They were probably coming around me because I was swatting at flies while brushing my horse. 

Bald-faced hornets are sleek and shiny, black and white, with very little hair.  The majority of the white is on the tail and the face, hence the name.  Their long thin wings frame their large body at rest.  They are actually wasps, not hornets, sharing the genus Vespidae with their smaller cousin, the yellowjacket. 

Despite the common family, bald-faced hornets eat yellowjackets.  This is why placing a paper-mache hornet’s nest over your picnic table is a good repellent for yellowjackets.  The fake nest will also repel bald-faced hornets because the hornets are territorial.  If they see a “nest” above your table, they are likely to avoid the area, expecting to be driven away by resident hornets if they come near.

It is common to find bald-faced hornet nests hanging in brush near a creek. They vary in size, from that of a goose egg to almost 2 feet in length.  They are made from wood and plant fiber that is chewed into a pulp by the insects and plastered into layers of cells for the larvae. The cells are covered by a gray paper plaster envelope.  As long as the nest isn’t near your house or in a high traffic area, consider leaving it alone, since the hornets do a good job controlling other unwanted pests.  They are also important pollinators.  If you try to remove a nest, the hornets will become quite aggressive.  Their sting is more painful than that of bees, because it contains different chemicals, and they can sting more than once.  They are also unique in that they can squirt their venom, so watch your eyes! 

Dangling Legs = A Gentler Wasp:  The Paper Wasp.

Like the bald-faced hornet, the paper wasp can sting more than once, but it rarely stings at all.  However, people encounter paper wasps quite often, because they are notorious for building their nests around homes; under eaves, porches, steps, greenhouses, doghouses, trash cans, and birdhouses.  I once dealt with a large nest in the door of our old truck.  Paper wasps are most likely to sting when defending nests.  The rest of the time, they are non-aggressive, and benefit your garden by pollinating flowers and eating caterpillars and beetle larvae.

Paper wasps have long legs that dangle during flight. This feature is the most helpful in distinguishing them from their aggressive cousin, the yellowjacket.  Paper wasps also have a much thinner “waspy” waist than their stocky yellowjacket relatives.  Slenderness and yellow color distinguish them from the bald-faced hornet.

Paper wasps make open-faced nests, usually with a single layer of cells that face downward.  This gives them the nickname “umbrella wasp.”  The cells are open until the larvae reach the pupal stage when the adults cover them with a white paper-like plaster.  One can usually see both open and closed cells in the nest.  Interestingly, paper wasps apparently will not build a nest on a surface that is light blue, so using light blue paint can reduce nest building.  However, paper wasps are sometimes attracted to bright colored clothing and perfume, so be cautious when you look and smell like a flower!

Paper wasps forage by day and stay at the nest at night or when it is cold.  Therefore, late evening or rainy cold days are the best times to remove nests. There is a better chance of removing most or all of the workers, and the wasps are not able to fly as well in the cold.  If not enough workers are removed, you will be amazed at how fast they can rebuild the nest!

Picnic pest:  The yellowjacket.

While the yellowjacket is also beneficial in reducing insect pests in your garden, it is difficult to see it as anything except a pest.  Yellowjackets are happy to invade your picnic or BBQ, damage the fruit in your orchard or raspberry patch, or even destroy beehives.  They have broad eating habits and will even feed their own healthy larvae to other larvae. They are sometimes as aggressive with one another as they are to humans.

Yellowjackets are the sturdy look-alikes of the gentler paper wasps.  However, they fly with their legs tucked under them.  Yellow and black, hairless, with long thin wings, they are hard to confuse with the gentle fuzzy honeybees and bumblebees that will not invade your lunch.

Yellowjackets are mostly ground nesters, as anyone who has ever stepped on a yellowjacket nest can confirm.  Nests usually start out in old rodent burrows, and can grow as large as a watermelon by the end of the season. Nesting colonies do not overwinter.  Instead, a solitary overwintering queen starts anew each spring.

Fortunately because of their voracious eating habits, yellowjackets are relatively easy to trap.  If you start very early in the spring, you can significantly reduce yellowjackets around your home.  Pheromone traps, sold at most hardware stores, can be highly effective if hung just as the daily daytime highs reach 60 F in the spring.  The key is to catch the queen before she starts a nest.  Catching the queen means that she will not be able to produce the hundreds to thousands of workers that will bother you the rest of the summer.  Hang traps on the east or south side of fruit, aspen, or other deciduous trees, in the middle of raspberry beds or in other areas where you noticed yellowjackets the year before.  Traps should be 4-8’ off the ground.  If nothing comes to the trap in the first week or two (and the weather has been relatively warm), move the trap. In a good location, a trap may catch hundreds of queens in a matter of days. Note: be sure to purchase traps only attract wasps, and not beneficial bees such as honeybees.

Later in the season, worker yellowjackets may be caught by a variety of bottle or water traps.  Just check out Google or YouTube, and you will find dozens of possibilities. Yellowjacket dietary preferences change during the season from fruit to meat, although a combination of bait such as beer, jam and sausage is tempting in all seasons. Do not use honey or fruit juice for bait or you may trap beneficial bees.  Finding yellowjacket nests is tricky at best, unless you are unlucky enough to step on one.  If you do so, remember that most people can run faster than wasps can fly.  Shaking them free from your clothing while you dash off is your best option.