OK Michael since you asked and glad to see others chiming in. First a disclaimer. I am not a scientist or a chemist. I'm a guy with a high school education trying hard to keep my small honey producing operation healthy and profitable, been at it for 40 years. I have been using liquid formic, without incident, since learning about it at the Simon Fraser Univ. Bee-master Course in 98. 

Safety tips! Formic vapor is heavier than air so always keep the product and pads below you at ground level. I wear heavy rubber gloves and a 3M 8577 Nuisance level organic vapor mask. They are comfortable in the vale and don't interfere with the reading glasses I now need to see eggs and larva. I get no hint of formic fumes with these. I stack the pads in alternating directions, holes down, layers of 2, in a 2 gallon bucket with tight lid and add 25ml of 65% formic each pad. So a typical application for me of 20 colonies would be 40 pads and 1,000 ml of acid. I do this the night before application and to ensure even saturation I invert the bucket the next morning for a couple of hours. The pads come out evenly wet but far from dripping and the alternating layers are easy to pick up with the needle-nose pliers I handle them with. 

At the yard, bucket at ground level, pop the lid (I use inner covers and telescoping tops) pull the old pads if any, scrape any accumulated propolis and lay the new pads down holes up one in the front third of the box one in the back third, lid back on. Total time less than 45 seconds. No smoke no hassle. The bees flee the new pads like beekeepers from a collection plate.The inner cover gives about 1/2 inch of air space for good evaporation. All are 2 deep colonies. I find here in dry and hot SE WA that the pads are totally dry and being pulled apart in 5 days. I have heard from others in cooler moister places that the formic evaporates faster than the water leaving moist pads but little formic smell after a week. 

My philosophy. What I am aiming for is the least disruptive but still effective fall varroa control. I started with 40 ml per pad, way to hot, and got the brood kill I was trying to avoid from using MAQS. Then tried 30 ml, way better but still some brood kill and egg laying disruption. For the last 2 years this the 3rd I have tried 25 ml (50 ml total per dose) with good results. The first round goes on the same trip as the last supper comes off. The second about 2 weeks later. Last year bad weather prevented a second round but I still had low counts and excellent winter survival. I believe that in the narrow window of 3 or 4 weeks max, for me, between suppers off and cluster forming cold, I can't afford any break in the winter bee rearing.

A brief review of my annual mite treatments. It is easy to say monitor your mite load and treat when you pass the threshold. I am suppered from late April until the end of August so no treatments in that time. I suppose I could get down to the brood box on my 6 high colonies in July and do something with formic but at 70 and hot and tired it ain't going to happen. For maybe 5 years I have used what I call the Alberta plan, as in Canada eh? Apivar (before that I confess it was Taktic) in the first 50 degree days in very late Feb. usually early March. Don't go any farther than to asses the population and put in 2 or 3 strips in the cluster. Later in early April I go through and make sure that they are queen right and relocate the strips to the growing brood nest as necessary. 40 to 50 days later the strips come out and suppers go on. I don't even bother with mite counts in the theory that I'm not going to do anything anyway and ignorance is bliss. Mid August at the end of a fruitful season I'll do some counts to get an idea of where we are. Then the described formic treatments, 2 max with counts between the two and after the last. On a sunny day in Nov. that might reach 45 or 50 I do a OX dribble (this year trying a vapor treatment on a few for the first time)

This falls counts/results. Pretreat counts on 8/17 and 8/20 of 6 colonies followed by counts 14 to 17 days latter of the same 6 colonies after the first round and the day before applying the second round. 9 to 4, 12 to 4, 8 to 3, 16 to 5, 4 to 0, and 12 to 6. The day after treatment here at home I see some small bee death, maybe 15 or 20 on the entrance and maybe a few dead larva. 7 to 10 days after the first round I went through all colonies and saw that they were all queen right with good young brood and eggs. The second treatment is on now, just came in from doing 2 yards. I'll do a final count on the same 6 in a couple of weeks and report.

I welcome critique from others on the list and would love to here how you use liquid formic with as much detail and counts as you can provide. As far as legality, I carefully consider what I think is morally and environmentally justifiable and try to do the right thing but here at Trial & Error Apiaries "We don't need no stinking badges". Thanks in advance.

Paul Hosticka
Dayton WA

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