Checked Varroa drop - one hive scored 3 in three days, the other one scored 6. Put the scores into the DEFRA website and it told me not to treat for 11 months. (Rejoicing about that, too... but a little scared as Varroa worries me and doing nothing seems wrong.) If any of you have suggestions that would go against DEFRA's advice, I would like to hear them.
There are a number of beekeepers on here who will state, categorically, that you should treat for Varroa ... even with no tangible sign of dead ones on the floor. My view (and a growing number of others) is that you should be sure that you have an infestation that needs treatment before you treat. We are led to believe that ALL colonies are infested to some extent but, if you have a thriving, healthy, colony then they may, possibly, be coping well with the levels of varroa and treatment just weakens any natural resistance or ability to deal with it.
Before you treat I would suggest that you do two more reliable tests than a simple drop test:
1. Uncap some drone cells and inspect them for signs of varroa. You may need to pull the contents out of the cell to see exactly the state of affairs. If there are varroa found in a number of cells then you have an indication that the infestation is fairly serious and needs attention.
2. Put a handful of bees from combs that have capped brood into a jar with a mesh top (a kilner jar with a disc of mesh cut to fit is ideal). Drop some icing sugar into the jar through the mesh and give the bees a gentle shake so that they get covered in the sugar. This will cause the varroa to drop off the bees and after a few minutes you can turn the jar upside down and out will come the sugar and any phoretic varroa that were on the bees. If you know roughly how many bees you have in the jar you can use the FERA calculation to determin the extent of the infestation and treat accordingly.The bees will not be harmed and can be put back into the hive.
2a. You can do the same test as at 2. above but instead of using icing sugar use surgical alcohol which will have the same effect of removing any phoretic mites but, clearly, will kill the bees - although you can then accurately count the bees in your test.
Armed with some real information you can then decide what level (or if any) treatment is required.
Obviously, those people with larger numbers of hives would find this level of investigation a bit of a chore and it is, probably, more cost effective and less time consuming to just treat as JBM suggests. But I am of the opinion that bees benefit from less treatment if it is at all possible and that, perhaps, in the future we can look forward to stronger colonies that are able to manage the threat from Varroa with less assistance from us and perhaps the mites will not develop the immunity to current treatments in the way they evolved immunity to pyrethroids.
Clearly, if the colony is heavily infected then it's a no brainer - they will need some treatment prior to winter and you then have choices about what you use. And that's not a can of worms that I want to open again here ...
Lots of previous (and occasionally warm) threads !
(don't tell Finman) In a way it's lucky the poor spring and it's mortalities scuppered my original plans or I'd be panicking about kit shortage now (better get Mam geared up for the sales methinks! 
