Wasps stripping off wood from my garden furniture
My garden furniture looked very unsightly with white blotches at the end of last summer (Fig. 1). There was scarring on my wooden garden chairs by the pond even though I had used an outdoor furniture preservative in the spring to seal off and protect the wood. The damage was caused by social wasps.
New teak garden chairs, which I mistakenly thought would be immune, were seriously affected last year and even small parts of my recently repainted red cedar wood shed were damaged. Most of this damage occurred from July to September. At the wasp populations increased there seemed to be a continuous procession in fine weather of one or two wasps stripping off the teak wood and departing to take the chewed wood back to the nest(s).
Fig 1. Garden chairs damaged by wasps (Above Teak chair and below Unknown wood type) - Photos © Lena Ward
I photographed a culprit wasp in action. It was either a worker of the Common wasp Vespula vulgaris or the German wasp Vespula germanica. It is difficult to be sure from the photo because the view of the thorax and head is not very clear and patterns on the abdomen of the workers are variable. These species chew off strips of wood, and then mix them with saliva and glue them together to make a sort of paper which becomes the outer shell of the wasp’s nest. Nests of both these wasps are usually sited underground but occasionally in dense bushes. The common wasp is more likely to be in wall cavities and attics associated with man, and the German wasp more likely to be outdoors.
Fig 2. Wasp in action chewing off the wood of a garden chair - Photo © Lena Ward
There are deterrent solutions that can be painted onto teak furniture, but I have no practical knowledge of these. It will also be useful to reduce the wasp populations locally by removing any nests. I did notice a small nest in in my garden a few years ago in a shrub of mock-orange blossom (Philadelphus lewisii). The garden shed also often has very small starter nests on the underside of the roof which are presumably where wasp colonies founded by the queens have not established properly.
The garden shed also often has very small starter nests on the underside of the roof which are presumably where wasp colonies founded by the queens have not established properly.
Fig 3. Wasp nest in Mock-Orange Blossom shrub - Photo © Lena Ward
Many animals learn to avoid stinging insects like wasps. Indeed, other harmless species may mimic the appearance of wasps and even their movements which presumably provide them with some protection from predators which would otherwise find them good to eat. This applies to the many common Hover flies (Syrphidae) as well as to adults of the wood boring Wasp beetle Clytus arietus) which I sometimes find in my garden.
Wasp Beetle, Clytus arietus (Cerambycidea) imitates the yellow and black warning colours of wasps. (seen on my garden hedge) - Photo © Lena Ward