OK , I'm back again so I'll try to finish off my previous posting.
Treating nests without forethought may actually increase the number or duration of nuisance wasps that may then attack hives for honey. I would like to clarify first what I mean by nuisance wasps. In my book, nuisance wasps are those worker wasps from a colony which has gone into decline after maturation with the release of its sexual progeny. Essentially, nuisance wasps are worker wasps that are scavenging for sweet liquids because there aren't any grubs left in the nest. These workers are technically 'on their way out' i.e. starting to starve from a lack of food.
Back to the explanation. Wasps are able to identify and recognize each other on sight and recognition is confirmed by active communication between wasps. This behaviour is critical to wasp survival, no more so than in the way that they protect their food and their nests. Considerable research work has been done in this field where sentry wasps have been mounted (glued) onto wooden pilums and their levels of aggression measured in response to recognition challenges. The heads of wasps from the sentries own nests' together with the heads of wasps from different colonies were presented to the sentries and the 'fight' response measured. In 100% of cases, the sentry wasps were able to identify foreign wasps.
If you have ever watched wasps returning to a nest, you might perhaps have noticed that they stay outside of the guarded entry point adopting a defensive, dancing flight before finally entering. Actually what is happening is that the returning wasps are waiting to be recognized and are waiting for confirmation from the sentries to be allowed into the nest. Without that grant or permission of entry the returning wasps won't enter the nest. Infact, if they tried to enter without permission the sentries would kill them. This sentry recognition and affirmation behaviour leads to a very interesting phenomenon when it comes to nest treatment. Invariably, when insecticides are used to treat a nest, the first wasps to suffer are the sentries. This results in the loss of the recognition and affirmation process for returning wasps which means that they don't (ever) enter the nest and are therefore not killed by the insecticide.
It also means that if the nest is in its growth phase, i.e. the worker wasps are getting their food from their grubs, that this food source will be denied to them essentially prematurely creating nuisance wasps that then need to find an alternative source of sweet food, e.g. honey from hives. At any one time there may be anywhere between 1,500 to 4,500 worker wasps outside of a nest at any one time with about 200 to 500 wasps in residence. Treating a nest at the wrong time of year may therefore cause rebound problems. After nest maturation, all nest treatment reduces nuisance wasp numbers. Similarily, treating nests first thing in the morning, i.e. just before first light, is more likely to be successful because it will catch all of the worker wasps when they're 'home'. Treating during the day is far less effective.
Anyway, if you decide to treat the nest yourself, this is something that you should consider.
Professionally (as a pharmacist), I have to warn you that wasps are hazardous and they pose a serious health risk (especially with the recent emergence of medical data regarding Kounis syndrome) and it is probably wiser to use the services of an external contractor. Just for the record we are not a pest control company and don't offer or provide pest control services. Our specialization is limited to our product (that I shan't mention), and the integrated management of wasps. Not only am I keen to help bee keepers protect their bees but more importantly as a healthcare professional, my principal concern is trying to prevent the estimated 1,000 to 1,400 people that may be dying from wasp stings each year.
Best wishes,
Karol
Hi Karol, we met at the beginning of the year and a most interesting day it was too.
I do have some points about the killing of wasp nests that I would like to mention though.
As a pest controller, I kill many hundreds of nests each year, this year being particularly busy, over 600 nests already and we are still not into August.
You state that when a nest is treated and the guard wasps are dead, no other foraging wasps returning to the nest will enter. This is not what I have experienced in my day to day wasp bashing exercises. I will explain…
You are probably more than familiar with the powder type treatments I.E. FicamD and such like. I have treated many nests which are located some distance away from the actual entrance to wherever the nest is located, basically none of the powder has touched the nest and I am reliant on the foraging wasps returning to the nest to carry the powder into the nest to kill it. I haven’t failed to kill a nest in these situations yet.
The recommended dose of FicamD per nest is 30 grams. I have weighed 30 grams of FicamD and it is surprising just how much 30 grams is in quantity.
It takes on average about 5 minutes to kill a wasp once it comes into contact with the powder. The guard wasps are not dead instantly, however reluctance to go into the entrance by foraging wasps is instant after treatment.
You could argue that the guards abandon the entrance as soon as treatment is applied, which prevents foragers from entering I suppose, but I will address that in a moment.
After treatment I have watched the activity for a considerable time. What I have witnessed is an instant reaction from treatment, with foragers reluctant to enter, this goes on for about 20 minutes after which they do go back in, but not before looking for any other possible entrance into the nest.
An hour after treatment the nest is dead. No activity.
It could be argued that the foragers have given up after this time and left (guard wasps dead and all) but what about the nests that I have attended where some clients have blocked the entrance with expanding foam, blue tack, mastic or some other wonderful creation and the foragers are still trying to get in a day or two after the entrance was blocked?
If the majority of foraging wasps do not ever enter the nest and die, where do they go? If this were the case, common sense would dictate that immediately after a large nest was treated there would be thousands of homeless wasps causing a nuisance within the immediate vicinity of the nest, but this is never the case.
I am not trying to imply that you are wrong or I am right, all I am saying is what I am witnessing is different.
Regards
Paul (Wasp Control UK)
