I did a 24 hour Varroa drop count yesterday. This involves clearing the removable hive floor and counting the Varroa mites which drop out of the hive over a 24 hour period.
I counted
These are very high numbers of mites for this time of year.
I have seen a worrying number of Varroa bodies on the floors of my hives. This is particularly concerning at the start of the season because it suggests much higher numbers of the mites later in the season. If I was a conventional bee keeper I would treat the hives now. I'm not going to. We'll see what happens.
There is very little to report from my hives in Oxford. They're bringing in pollen; there are Drones leaving and returning; there are very few Varroa falling onto the base board*; there are lots of wasps but none getting into the hives.
It's all very calm.
* maybe a dozen between the 4 hives
Colony 13 is dropping Varroa. They are also cleaning out old comb so there is a lot of debris on the hive floor. I found 2 or maybe 3 Varroa bodies.
This colony is new to my apiary, having been established elsewhere. I haven't really included it in my Varroa Zero post because it's new. Hives D and G are included. There were no Varroa on the floor of either this morning. There doesn't appear to much activity in Hive D at all. I shall have to check them.
I regularly examine the floors of my hives. The stuff which falls out of the hive tells a story about what the bees are doing. I always look for Varroa mites. I've found none on the floors of any of my hives for several weeks. I don't know why.
I visited my out-apiary today and examined the removable hive floors for evidence of recent activity.
Three hives (D, F and G) show evidence of recent brood emergence. There were also hundreds of dead mites. Hive D had been especially prolific. There was also crystallised sugar which suggests that old honey is being eaten or cells are being cleaned out.
Hive E is having a Varroa mite crisis. I checked today and for the previous 2 weeks. Each time I found hundreds of dead Varroa mites.
High mite drop can be a factor in colony collapse. I don't expect them to perform well next season - if they survive through the winter. I expect them to be weakened, and any brood raised in early spring will be heavily infected with Deformed Wing Virus or other diseases symptomatic of Varroosis.
I moved Hive H from my garden to my out-apiary on Friday 30th June. I looked at the removable floor today and found 1 Varroa mite. Just 1 in 8 days. Compare that to Hive H which was dropping 20 per day as a new swarm.
The colony in Hive H has been feral for some time. The colony in Hive F had been a standard bought Buckfast queen 2 or 3 years ago. It's possible that the feral colony is adapting to Varroa and has managed to limit its' numbers. The mite is still present - it's endemic and won't now go away.
I'll see how Hive H fares as it settles in.
I looked at Hive F's removable floor again on Tuesday 9th May. I counted 24 Varroa mites which had fallen out of the colony. That's 8 per day. Will they survive?
UPDATE: I visited the hive on 12th May after dark. There were another 32 mites. I've counted 88 mites in 7.5 days, an average of about 12 per day. That's very high. This colony has been untreated for a couple of years but it was from a bought queen before that. I don't think much of its' ability to manage Varroa.