Last time I checked my hive on organic Frogmore Farm at Toller Porcorum I noted that the brood was spotty, there was lots of bald brood and one or two bees showing signs of Deformed Wing Virus. I treated them with a dribble of Hive Clean, which I haven’t used before, hoping that it would improve matters. It didn’t!
Today I went along with some formic acid. I had a hive with similar symptoms last year which I treated with formic and it restored them to health.
Formic’s nasty stuff to play with. Years ago I dribbled some with a syringe onto a brood box that was badly afflicted and all the bees started fanning frantically, sending a cloud of formic laden air in my direction! I rapidly decided that it would be a good idea to move upwind!
Rather than splashing about with large amounts of acid in the apiary, last evening I brought the formic home from where it lives, found a plastic drink bottle, washed it out, removed the label and made 2 other labels, one reading ‘FORMIC ACID, CORROSIVE’ and the other vertically to act as a volume measure. I placed the bottle with a funnel on the kitchen scales and re-set them to zero. Then I carefully dribbled in water until the scale read 40 grammes. I made a mark on the label and then added another 40 grammes, marking again. I recall from my schooldays that a cubic centimetre (cc) of water weight a gramme, hence a litre weighing a kilogramme. I have no idea other density of formic acid compared with that of water but they can’t be very different and ‘near enough is near enough’!
I went into the garden and, keeping a curious cat at bay, gingerly transferred 80cc of formic to the container, leaving them in the garden overnight.
This morning I went to Frogmore, got kitted up and went to the bees. The books tell you to wear rubber gloves when handling formic. I had some with me but decided not to use them as they increase clumsiness and thus the likelihood of things going wrong. I did, however, have a gallon of fresh water with me in case I needed to rinse off a splash in a hurry.
A couple of years ago I bought a sheet of capillary matting to sit seed trays on in the greenhouse to keep them watered. I had cut off an 18″ square last year to apply the formic and it worked well, so I had it with me this time.
The hive is less than 50 yards from a massive badger sett, down which one could lose half a class of school kids! They once destroyed a hive there, so nowadays the fencing is as badger proof as I can make it, which makes it also awkward for me to get in and out!
The bees were very busy and good tempered. I gave them a drift of liquid smoke and veiled myself while it took effect. There was some weight in the supers so I suppose I shall have to extract some honey later on. I went through the brood chamber, observing brood in all stages but not seeing the queen. Lots of the brood was ‘bald’ many pupae at the ‘red eye’ stage. There were plenty of drones: that’s fine as they may pass on the genes for hard work and good temper around the area. I am assuming that the exposed brood is a symptom of hygienic behaviour by the bees doing their best to get on top of the mites, but I may be wrong.
I placed the sheet of matting upside down on the supers and carefully dribbled 40cc of formic on it, then placed it on the brood box where the queen excluder had been. I left a small gap for traffic to the supers and hope the queen doesn’t find it! I ought to have taken a plastic QE with me.
Having rebuilt the hive with a little extra ventillation in the supers I retreated, re-tied the badger fence and returned to the car to write up my notes. I shall leave the matting on for about 3 days, by which time all the acid should have gone and then repeat the treatment when I get back from Gormanston.