We are still using here in Canada and with great results. I cannot understand for the life of me, why it has not caught on South of the Border more. A fall and spring application (if needed), treat both Varroa and Tracheal mites with no fear of a resistance developing, unlike Apistan and Checkmite. Also, the residues from Formic acid are neglible, compared to Apistan/Checkmite strips. We have been using 4"x5"x.25" foam pads (the type of foam that florists use to mount floral arrangements in). The Foam pads are enclosed in shrink wrap, clear plastic with the bottom ends trimmed to expose the acid soaked pads to the air. The pads are are attached to the side of the uppermost Broad Box (open-end down: one pad per brood box) with staple gun and are left for twenty-one days (longer if the weather is lousy and cool, or there is a large infestation). After this period the dried-out pads are removed. Another benefit is the cost. To treat each two brood box colony with two pads, the cost is CDN$4.50, which is about US$2.75. A Miniscule expense when compared to the pharmaceutical chemical strips of Apistan and Checkmite. And don't forget, the Formic Acid treatment is acting against Varroa and Tracheal mites. No more menthol crystal expense! So what are the negatives, I have read that it is not as effective as the chemicals, but I have not read any hard facts supporting this arguement (perhaps someone can direct me to these details). I've also been told that newly emerged bees, can also be adversely affected by the acid, but I've noticed no effects as such with our hives (ie. increase in dead bees at entrance, etc), nor has brood rearing been interupted. I suspect that the biggest problem with Formic acid relates more to the big business of the pharmaceutical companies that produce Apistan and Checkmite. As Formic acid is a naturally occuring substance (ie. Ants), there is no way big business can charge the arm and leg prices they do for there patented chemical strips. Hence, an effective lobby has slowed the acceptance and spread of information on the treatment. Another, problem maybe that the profit margins in selling Formic Acid are far too slim, thus none of the major bee suppliers/retailers have any interest in marketing this cheap product, especially given the much fatter margins earned flogging the chemical strips. The gel packs and foam pads (that I believe are far superior) have solved the problem of how to deliver the formic acid treatment, the only problem that remains is getting the word out to general beekeeping population. If anybody else has any further information on Formic Acid (ie. treatment delivery, negatives, marketing, etc), please let me know. I'm still confounded as to why people are so reluctant to adopt the treatment. By the way, we've lost no hives to mites, have very low levels on all hives, healthy populations, good yields, and have developed no resistance to Formic acid treatments. Cheers, Mark Walker.