Varroa Treatment
 
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Varroa Detection

Testing for varroa can be achieved by various methods, some of these use the same materials as for treatment and some are completely different.

Natural Drop

This requires very sharp eyesight as the mites are easily missed and a couple of missed mites in a count represent a much bigger infestation that may be inadvertently ignored.

Hard Chemical Diagnostic Methods

Bayvarol, Apistan and Taktivar may be used to monitor a 48 hour mite drop (onto sticky sheets so they cannot run away). Consult the instruction leaflets that come with the chemicals. It is possible that there are other veterinary materials that can be used in this way.

Tobacco

This was the earliest method used in the UK. It has serious drawbacks in that it is not very effective and causes some damage to the bees. I believe it was the method that was used in the test that discovered the first mite in UK.

Drone Larvae Varroa Test

The uncapping fork test is not a replacement for the mite drop test, but is a useful additional tool.

Do not just uncap the first few drone brood you meet in a hive, it is necessary to uncap 100 cells or more, and see no mites, to be reasonably sure that the hive is not infested.

The best tool for this test is the type of uncapping fork with bent prongs. Use one prong to uncap odd cells to establish the age of the larvae. When you find a group of drone cells that are at the pink eye stage... Insert the whole fork from the side so that the prongs will go through the thoraxes (thoraces?) of the grubs... Lever out an area roughly 65 mm square.

You need to use grubs of the right age otherwise they are too mushy and your actions will result in much mess and no information.

You also need an adequate supply of drones (most beekeepers seem to avoid producing them in the mistaken belief that they will get a lower honey crop if drones are produced).

Ether roll, Methylated spirit, Machine oil

Are all very similar methods of floating the mites away from the bees in order to count them.

The ether roll method

This method can be performed any time during the season, but at different times of year, there will be a varied number of mites that are in brood cells, the number of mites counted will vary according to the season and should be taken into account.

Collect a known quantity of adult bees (approximately 300) in a jar by scooping the mouth of the jar across the occupied surface of a comb. Consolidate the bees at the bottom of the jar by rapping the jar sharply on something solid. Spray the bees for two seconds with of car engine starter aerosol (which contains ether).

Replace the lid and both shake and roll the jar so that varroa mites can be observed sticking to the inside of the jar.

Ether is highly flammable, avoid lighted smokers.

The methylated spirit and machine oil methods

These are both flotation methods, whereby a known volume of hive debris or a known number of worker bees is introduced to a larger volume of either methylated spirit or light machine oil in a beaker. The mixture is stirred thoroughly and any varroa present will float up to the surface for counting or estimation.

Sugar roll

This is a simple, non chemical, inexpensive and non destructive way to test bees for the degree of infestation of Varroa mites.

A Kilner jar with the glass centre removed from the lid and replaced with a disc of 8 mesh can be used. a funnel made by cutting away the bottom portion of a conventional plastic funnel so that the hole in the bottom is about half the width of the mouth of the jar. You may need to hold this in place with a little 'Blue-Tack' or plastocene.

A volume of bees from the brood nest are shaken over the funnel until there is an adequate amount in the jar (calibrate the jar with lines painted on the outside). Put on the lid with mesh.

A tablespoon of icing sugar (powdered sugar) that does not contain corn starch is poured through the mesh and the whole jar shaken to coat all bees with the powdered sugar. Be consistent with the time, two minutes of shaking has been recommended.

Then the jar is then inverted and shaken over paper or a plastic tray or even a bowl of water, which dissolves the sugar and makes it easy to count exactly how many mites have been removed. The bees can then be returned to the colony as they are still alive after the test.

Varroa Calculator

There is an online interactive calculator, provided by the UK Central Science Laboratory... Click on the link below.

Varroa Calculator

There used to be a plastic circular 'slide rule' varroa calculator that was available in UK, I will detail it when I unearth the one in my 'filing system'.

Printed from Dave Cushman's website Live CD version

 Written... Summer 2000, Upgraded... 23 July 2005, Additions... 20 September 2005, Upgraded... 13 May 2008,
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