BEEKREEPING & DEVELOPMENT 46
VARROA!
A RESEARCH PROGRAMME has
RECOMMENDATIONS
recently started in the Caribbean island of Grenada to validate the efficacy of essential oils as miticides. We are placing special emphasis on locally-produced oils: cinnamon, clove, mace and nutmeg. We are considering the possibility of offering a commercial ‘apimiticide’ made from Grenadian coconut oil, Grenadian beeswax and Grenadian nutmeg oil. It sounds really nice!!
We have not yet carried out trials to determine the best time during the bee calendar for these treatments. However we | have made the following assumptions: |.
ingredient, the risk of obnoxious contamination of hive products is negligible. .
Do not accuse us of putting on the saddle before bringing in the horse! I must explain that this essential oil cream treatment has been used by the beekeeper who first reported Varroa present in Grenada. He has found high levels of Varroa casualties, and importantly a lack of any noxious effects of the treatment on the bee colonies. Also the number of worker disabilities resulting from the viruses vectored by the mites has been reduced almost to zero. Quite a relief from the pitiful sight of thousands of crippled, crawling bees of recent times.
M
EMERGENCY TREATMENT
450g coconut oil (or any vegetable cooking oil) 15g essential oil (we have tried eucalyptus, nutmeg, peppermint and spearmint)
Preparation
2.
3.
Stir until the wax melts completely and allow to cool to 42-45°C. If a thermometer is not available, cool until the mixture just starts to harden at the surface, but is still quite fluid.
Trees beekeepers use in Grenada
distributing it evenly.
FOUR
COLIN CALVER
Push the strip deep into the entrance of the hive undergoing treatment, preferably before 0900 hours on a hot, sunny day. If Varroa is present, the first effects of the treatment (dead or terminally ill mites on the bottom board) can be seen within 2-4 hours. Presumably the hotter and drier the weather, the faster the effects.
The above mixture should be sufficient for 50 hives if applied as follows:
On one side of the strip spread one or two teaspoons of the miticide mixture,
‘
4.
TREATMENT
2.
nutmeg and mace growing
Leave a one cm section at each end of the strip clean to avoid getting mixture on yourself.
the mixture until thoroughly blended.
Cut strips from any of the following: bamboo, Bristol board, cardboard, plastic containers, plywood, or tins. The strips should between two and five cm wide by 20 cm long.
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3.
At this point stir the essential oil into
I.
Based on these assumptions, and with due regard to the local climatic and floral characteristics of the apiary and foraging area, beekeepers would be well advised if they apply essential oil treatments against Varroa not less than one month before the main nectar flow. This is as a
I
170g beeswax
Break the beeswax into small pieces and melt in a double boiler (a large pot with water containing a small pot with the wax} with the coconut oil.
Essential oil treatments for parasitic arthropod control in honeybees does not negatively affect colonies or individual bees, in their physiology or exchange of pheromones.
general sanitary practice.
THE ‘MAGIC’ FORMULA IS:
1.
Due to the natural (as opposed to man-made) nature of the active control
5.
After 24 hours (longer for lower temperatures}, the treatment is over and a number of dead Varroa can be seen under the brood chamber. Also, and possibly for the first time, white males can be observed dead on the bottom board or groggily walking about in a totally uncharacteristic behaviour.
This is advisable in cases of extreme infestations, manifested by direct observation of Varroa in capped drone cells, dead mites on the bottom board, proliferation of handicapped workers, and drones crawling in and out of the hives. That is an overall colony ‘demobilisation’, with a consequently sharp decrease in honey production and pollen gathering.
experience that even colonies considered beyond redemption can be saved by these treatments if applied to populations of more than 10,000 bees. So far we have not had any losses of colonies due to severe re-infestation, as the treated hives have been able to achieve self-reliant populations. It has been our
The October-November 1997 rainy season was the driest have seen in 20 years in Grenada. We have concluded that during periods of heavy rain bee colonies in tropical conditions are at their weakest point in terms of resistance to Varroa infestation and proliferation. Therefore, we have seriously considered advising treatment prior to the onset of the rainy season, |
As you can appreciate, our smiles continue to widen when we think about the future of beekeeping in Grenada, as far as Varroa is concerned.
A Bees for Development publication
