Wasps and yellow jackets

Wasps and yellow jackets

Complaints about wasps and yellow jackets soar in early fall.  The populations of these critters is high now and they are intent on preparing for winter and not as tolerant of humans as they were earlier in the season.  Wasps and hornets are beneficial insects and if at all possible they should be left alone.  After a hard frost the problem will go away.  But in some cases as when the nest is near a doorway or there are severely allergic people that may be impacted they must be dealt with. 

Bald Faced Hornet - bugguide.net

Wasps and hornets aren’t quite the same family as bees, but since they look similar and have the same ability to sting, people often lump them together.  Some wasps and hornets do pollinate plants but others are predators of other insects that harm plants, or they consume dead plants and animals.  As a whole all bees, wasps and hornets should be considered as beneficial creatures and we should be rooting for the survival of all of them, not just honeybees.

Wasps come in many colors.  Many don’t bother humans and don’t nest near homes.  Mud daubers, yellow jackets, bald faced hornets and paper wasps are the most common wasps people consider to be pests and yellow jackets are by far the most aggressive. 

Yellow jackets are striped yellow and black insects that many people mistake for honey bees. (Honey bees have tan hair on their bodies and flattened hind legs to carry pollen.)  There are several species. The Eastern Yellowjacket (Vespula maculifrons)and the German yellow jacket (Vespula germanica) are the most common in the northeast. 

Yellow jackets build papery cell homes inside crevices or even in holes in the ground.  When the home area is vibrated or stepped on they may swarm out in a vicious protective mob. They are aggressive and don’t need much provocation to sting, especially in the fall.  In the fall populations of yellow jacket colonies are large and the insects seem to become more aggressive as numbers build up.

Paper wasps are black with yellow markings.  There are twenty-two species of Polistes family wasps in North America.  They can be hard for the average person to distinguish from yellow jackets.  Their nests help separate them.  Paper wasps make the papery flat nests dangling from a stalk consisting of many cells that open downward.  These nests are often under the eaves or overhangs of homes. They are made from chewed wood mixed with salvia.

Paper wasps treat the stalk of the nest with a secretion they produce to repel ants, which like to eat the wasp larvae.  Paper wasps protect a nest territory, which may be a problem if a nest is above your door, but are not otherwise aggressive.  They are good pollinators and feed on caterpillars and beetle larvae and should be left alone if possible.

Bald faced hornets (Dolichovespula maculate) are black with white markings on their face, thorax and abdomen.  They are the builders of those impressive papery cone shaped nests dangling from trees that teachers and naturalists like to display in their classrooms. Only the queens survive winter, usually by hibernating in a crevice or hole in a tree. The nests are not used a second year and after a good freeze it’s safe to remove the nests either to dispose of them or to use them for decoration.  Beware – there may be other insects hiding inside after the wasps are gone.

Mud dauber- wikimedia

Mud daubers are black with a narrow thread like waist attaching the head to the lower body. Some are marked with yellow, but the very narrow waist distinguishes them from yellow jackets and bees. There are several species. (Sphecidae or Crabronidae)   Their nests look like balls of mud linked together in a mass or sometimes a single lemon sized mud ball. Some species also make long tubular mud columns.   There is an opening in the bottom of the mud nest.  Mud daubers are not very aggressive and seldom sting humans.  They prey on spiders so if you don’t like spiders maybe you should leave them alone.

Treating and removing nests

Dealing with wasps and hornets may mean removing a nest, but they can’t be relocated like honeybees.  Often they will need to be killed.  You can buy any number of wasp and hornet sprays to spray nests where they can be reached. These are quite effective if applied properly and won’t kill many non-targeted insects.  They are best used on yellow jacket, mud dauber and paper wasp nests, the football shaped bald hornets nest is hard to penetrate with pesticides.

You will need someone willing to get close to the nest and that person should not be one who is allergic to bee/wasp stings.  It’s best to deal with wasps and hornets after dark, using a red light or a flashlight with a piece of red plastic over the lens.  Cool nights are best.  A chilly rainy day can also be a good time to deal with wasps and hornets.  All wasps and hornets are less active in cool weather and after dark most insects will be in the nest being treated and more likely to be killed.  Wear long sleeves, pants and gloves when treating nests.

A garden hose can be used to wash mud dauber and paper wasp nests down.   A high pressure spray is best. This is simple and non-toxic.  Some nests may be re-built.  Keep a close eye on the location and hose down any rebuilding efforts as soon as possible.

The bald hornets large football shaped nest hanging from a tree may be hard to reach.  You could use a tree trimming tool on a long telescoping pole to trim off the branch the nest is on.  Place a plastic bag lined garbage can on the ground beneath the nest to catch the nest and quickly tie up the bag as it falls. 

If a ladder will reach the nest a plastic bag can be placed over the nest at night, the bag tied off and the limb the nest is on trimmed off the tree.  This is one time you may be able to move the nest, if you are willing to put the nest somewhere and remove the bag.  In the fall however the nests will be abandoned soon anyway.

Yellow jacket nests should be located by watching where the workers are coming and going from.  Watch for them in the middle of a warm, sunny day when they are most active.  Mark the opening so you can return at night and find it.  The nest opening can then be sprayed or dusted with pesticides.  Most spray cans have an extension nozzle so you can get the pesticide far inside the hole. Openings in home walls can be sealed shut with caulk after applying pesticides. Work silently and slowly when dealing with yellow jacket nests.  There are also traps and poison baits made to kill yellow jackets.  Follow the label directions carefully.

If dead wasps and hornets fall out of a nest sweep them up so birds, frogs and toads don’t eat them and be harmed by the pesticide.  Dispose of them in a sealed bag.

paper wasp- wikimedia commons

Wasps and hornets after food

First recognize that both meat products and sweets attract wasps, particularly yellow jackets in the fall, which can make eating outside hazardous.  There are traps that lure and kill yellow jackets that you can buy, locate these far from the house or where you will be eating.  For a one time event such as a picnic you may be able to lure most yellow jackets  away by placing a shallow dish of orange or grape soda and a few pieces of hot dog at some distance from where humans will be eating.  Put these out an hour or two before humans begin carrying food and drinks around.  Also remove any hummingbird feeders near where people will be eating or sitting.

Keep food and drinks covered outside and clean up spills.  Trash cans should have lids and not be close to eating areas.  Yellow and white clothing or bright floral patterns may attract wasps as does sweet smelling perfumes and aftershaves.  Wearing a commercial insect repellant with DEET may help keep wasps away from you.

Despite many claims science has proven scents like eucalyptus, cucumber, mint, citronella, dryer sheets, bleach, ammonia and so on do not repel wasps.  There are no plants you can set on a table or plant to repel wasps.  Mothballs are extremely hazardous to humans and the environment but do not repel wasps.  If you or someone you know is allergic to bee and wasp stings relying on old wives tales, organic concoctions and myths to repel or kill wasps is foolish.

Yellow Jacket