VFindMe-Home Garden-Home Search

On ground nesting wasps

Diverting stingers

by : Nov 1, 2015

Some wasps build their nests in the ground. It might be a patch of mown grass plot, or in a cultivated garden. If you are lucky, you see them coming and going and know where they are living and just avoid them. If you are unlucky then you will find them while mowing grass or digging or clearing brush, at which point you may suffer many stings on exposed skin. If you have a family member who has a negative reaction to stings, or by chance they choose to build in a very inconvenient location then there is a lot of pressure to do something to make them move house.

Like bees and other insects, once the queen is established they don't like to move unless it is a natural part of their life cycle such as in swarming. Sometimes the only way to resolve the issue is to prevent access, so that the nest is deprived of resources. There are a number of suggested ways to destroy the nest, a couple being pesticides and drowning; these may work for you, however unless part of the nest is exposed so that you can apply the pesticide effectively that probably will not work, and if you are on sandy ground then even a large amount of water will not hang around long enough to drown them since the water percolates into the soil too quickly.

My setup

A method which has worked for me is to make it very difficult for the forager wasps to leave and re-enter the nest. Believe me when I say that putting down some fiberglass mosquito netting is not effective; the wasps will eat through it in no time. Aluminum is a lot more effective, but then the wasps will find a way around it if the patch is too small. We need to give them a real puzzle to find the way out and back in. For one nest I put down three layers of old landscape fabric about 8 feet square one layer on top of the other and weight the layers down with concrete blocks. I put down the fabric at night when all the wasps are in the nest.

How it works

This is the way it works: being old fabric it is dotted with small holes, some of which allow a wasp to pass. But the holes in one layer are not lined up with the holes in the layer above. So the wasps have to figure out which hole to use in which layer. They can escape with some work and can find their way back in, again with some work using a zig-zag path through the layers. But it puts a very heavy burden on their working efficiency. Keep an eye on the patch in succeeding days and you may see that they have found an easy way through to the edge of the fabric layers; if this happens put a heavy stone down to prevent them using that route. If one hole is too easy a route, put a stone on that too. It will be instructive to watch them collectively figure out what to do each time you block an entrance.

After about two to three weeks have elapsed, you may find that there is no more activity to and from the nest. In daylight, begin removing stones and layers. You will probably find a number of dead wasps between each layer of the fabric, those that made it so far but not far enough. Be careful when removing the bottom layer, you may see a dozen wasps leave the nest, finally freed from their prison, they will fly off to forage. However likely they will be the last of the population. Watch carefully and when you see no more wasps emerging you might want to consider digging the nest out so that when the foragers return they find the home site unusable and will abandon it. If you judge the nest to be still too active, replace the fabric the next night and start again.

Be careful

Yes, it is a strange and time consuming process, but it has worked for me. Wear protective clothing as necessary, paying close attention to good high boots and thick pants, wrapping thick socks around your ankles for extra protection.

Copyright © 2016