Treatments registered in Canada

Anne's August count comes back at four per hundred, well over the line. A friend at the farmers' market tells her about a homemade mite remedy that works wonders and costs almost nothing. Anne is tempted. But in Canada, using it would be against the law, and it might not even work.

Here is the first rule of treating mites. The label is the law. Under the federal Pest Control Products Act, you may only use a product that is registered in Canada, and you must use it exactly as its label says: the dose, the timing, the temperature, how long it stays in, and whether honey boxes can be on. Homemade and off label treatments are illegal.

Ontario's ministry keeps a current list of the Varroa products registered in Canada. Check it, and check the label, before you buy anything, because products and rules change.

The products fall into a few groups. Organic acids: formic acid and oxalic acid. Synthetic strips, with active ingredients such as amitraz. Essential oil products based on thymol. And a product made from hop beta acids. Each works differently, and each has its own conditions.

Temperature matters. Many treatments only work, or are only safe for the bees, within a temperature range. Formic acid and thymol products, for example, need moderate weather, not a heat wave and not a cold snap. The label gives the exact range.

Brood matters too. Remember that most mites hide in capped cells. Oxalic acid drizzle and vapour are meant for colonies with little or no brood, like a cold day in late fall. In spring, with brood everywhere, oxalic acid won't reach most of the mites.

And honey matters. Only some products are labelled for use while honey supers are on, including certain formic acid, oxalic acid strip and hop beta acid products. Synthetic strips never go on with supers in place.

Then there is resistance. In Ontario trials in twenty nineteen, two older synthetic products killed only about three quarters of the mites, while amitraz killed about ninety two percent. Now resistance to amitraz is starting to appear too. So rotate between product groups from one treatment to the next, and test after every treatment. Resistant mites are a reportable disease in Ontario.

One tool needs no chemicals at all. Because mites prefer drone brood, you can put a drone frame in each brood box in spring, let the colony fill it, and remove the capped drone brood every twenty four to twenty eight days, before the drones emerge. It lowers mite numbers, but on its own it won't do the whole job.

Now let's change one fact. Suppose Anne uses the same synthetic strip every fall for five years because it worked the first time. Each year, the mites that survive it breed. By year five, her count barely drops after treating. That is resistance, and rotation is how you avoid it.

The mistake beginners make is half treating: skipping an application, taking strips out early, or placing them at the edge of the brood nest instead of in it. A partial treatment kills some mites and trains the rest.

Here is the rule, in one breath. Use only products registered in Canada, exactly as the label says, match the product to the temperature, the brood and whether supers are on, rotate between product groups, and test again after every treatment.

That's the end of module six. Next, the other pests and diseases, starting with foulbrood.