Result!
Thirty four dead mites in the first 48 hours following treatment with my home made 'napalm' (see previous post). Another 10 or so mites will probably drop over the next 24 hours and then then the treatment effect will wear off. Overall oxalic acid is about 95% effective, so it looks as though there were about 40-50 mites in the hive; well within the range I had estimated in my last post.
Moreover, all the dead mites were fully grown adults. This is encouraging because it suggests that there is very little bee brood in the hive right now. Those adult mites (which are all female) were waiting for the queen to start laying again so that they could lay their eggs on the bee larvae. When the baby mites hatch they feed on the developing bees and grow, then reproduce and lay more eggs, so by the time the new bee emerges it's covered in mites and infected with viruses.
I doubt I've killed all the mites in the colony but they have certainly been knocked back. Once the queen starts laying again in the next few weeks there should be plenty of health brood, which augers well for a strong colony come spring.
Best of all the 'napalm' hasn't done too much harm to the bees; it's warm today and dozens of them were flying around the hive taking a 'comfort break'.
