Spice the mite with nutmeg

by Jorge Murillo-Yepes, B&D's Correspondent in Grenada

In B&D43 and at the recent Apimondia Congress in Antwerp. Jorge Murillo-Yepes spoke about the control of Varroa using a locally produced mixture including nutmeg oil. In this article he explains current, exciting progress.

RESEARCH PROGRAMME

A research programme has 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 commercial ‘apimiticide’ made from Grenadian coconut oil, Grenadian beeswax and Grenadian nutmeg oil. It sounds really nice!!

Do not accuse us of putting on the saddle before bringing in the horse! 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 relief from the pitiful sight of thousands of crippled, crawling bees of recent times.

THE ‘MAGIC’ FORMULA IS:

170g beeswax

450g coconut oil (or any vegetable cooking oil)

15g essential oil (we have tried eucalyptus, nutmeg, peppermint and spearmint)

Preparation

1. Break the beeswax into small pieces and melt in double boiler (a large pot with water containing small pot with the wax} with the coconut oil. 2. 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. 3. At this point stir the essential oil into the mixture until thoroughly blended.

TREATMENT

The above mixture should be sufficient for 50 hives if applied as follows:

1. 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.

2. On one side of the strip spread one or two teaspoons of the miticide mixture, distributing it evenly.

3. Leave one cm section at each end of the strip clean to avoid getting mixture on yourself.

4. 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.

5. After 24 hours (longer for lower temperatures}, the treatment is over and 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

RECOMMENDATIONS

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:

1. Due to the natural (as opposed to man-made) nature of the active control ingredient, the risk of obnoxious contamination of hive products is negligible.

2. Essential oil treatments for parasitic arthropod control in honeybees does not negatively affect colonies or individual bees, in their physiology or exchange of pheromones.

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 general sanitary practice.

EMERGENCY TREATMENT

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 consequently sharp decrease in honey production and pollen gathering.

It has been our 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.

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.