Testing for varroa can be achieved by various methods, some
of these use the same materials as for treatment and some are
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 inadvertantly ignored.
Hard Chemical Diagnostic Methods
Bayvarol, Apistan & 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.
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 65mm 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).
Ether roll, Methylated spirit, Machine oil