Bee survival percentages

[nemphlar]

I used FA thats formic acid this year for the first time. As I only had 4 surviving hives I thought I,d experiment on 1 hive only in case I managed get it wrong and wipe them out, I treated them 3rd July. The insulated eke along with the evaporator seemed to work ok and on 23rd I treated the other 3 hives
Just checked a 7 day natural bug count, the original test hive had 13 the 3 others had none. I dont have a lot of confidence in natural drop counts, but not to see any is curious

[The Drone Ranger]

Hi Nemphlar

I thought July was the recommended month for Formic

Just when Calum said it was silly because of re-invasion I thought he might be overlooking the killing of varroa in sealed brood.

Also I hear that there can be 10 - 20% of the open brood killed by the treatment so not something I would think for August and Sept you need the winter bees.

I am just guessing as I have only used formic a few times mainly because I like the smell of thymol

[nemphlar]

I think I'd agree DR. I didn't check pre or post treatment larvae count, but I did find some dead 3/5 day old larvae on the floor, assuming the bees dumped most of the dead out of the hive it's probably significant. If this were to happen in August,it ight be more difficult to recover. I still intend to use OA for winter. I think it was your data that showed zero natural drop prior to treatments, but still showed varroa after.

[Calum]

Hi
I am treating 30 hives. And my mentor has another 24 hives. We see about the same mite levels on 3 sites.
The reinvasion is a real problem, one of the institutes here set up a bee count on the entrances to hives in late Aug early Sept.
In one case they had more than 1000 bees entering the hive than left it on a days tally. The hive had not been robbed. Bees from other colonies that are collapsing will beg into other hives bringing their varroa with them.

Trying to get 5-7 treatments in starded first week August, every 5-7 days.. Fourth one done last friday. I use 60% formic acid, and try to treat when the temperature is below 25°C but above 18-20^C. I have not noticed any brood loss. When it has been too hot / the hives were unshaded I had that issue in the past, but the hives survived it.

[nemphlar]

Calum
Your running quite few hives for an amateur, do you think if you were able to treat them simultaneously it would make difference. Are all the hives in your area under your control

[Calum]

In the area I keep my bees there are a couple of hundred hives; in 2009 our club in Lindau had 49 beekeepers with 520 colonies.
There is another club in the town but they are not as big. Horbranz over the border in Austria about 5 km away also hs a club with about 30-40 beekeepers...
So not all hives in the area get treated at the same time, and there are always a couple of swarms that noone caught.

[nemphlar]

A bit more productive than our marginal west of Scotland then, had a wee look on google looks very nice

[Calum]

Big apple and pear growing area due to a really good micro climate around the lake..
Plenty of dandelion and clover between the tree rows, that is not constantly being mown for cattle feed, and plenty of mixed forest for 'wood' honey.. The varroa problem is immense though. the high density of colonies and some beekeepers that prefer to treat their bees once less instead of once more to save a few pence. The people in this area are renowned for having far deeper pockets and even shorter arms than even the Scots.

[The Drone Ranger]

Calum

have you tried using thymol instead ? it is acting over a longer period from each application so might take care of any new invaders .
I dont think it contaminates comb any more than Formic or Oxalic would

Thanks for the explanation by the way

[Calum]

Hi
I will probably give it a go next year just to give the varroa a different treat.
Oxalic and folic acids dissapate over time (they have from now till next may when I harvert). The oils in thymol build up in the wax apparently - I think that could become an issue if you always recycle your wax for frames or use exclusivley thymol.
I do treatments of 60% Formic acid 2ml / frame on a foam cloth from above. This method is only still recommended in Bavaria due to the need for a relativly high temps and low humidity. Long term treatment with 80-120ml 80% formic acid in a medicine bottle is more prevelant in the rest of germany and austria.