3. Keeping an eye on Varroa destructor, parasite of the honeybee. Long story short, humans moved the European honeybee to North America during the 1600s. Hives were kept for honey and swarming bees integrated into ecosystems around the country. In the 1980s Varroa destructor was accidentally moved from Asia where it coexists in a balanced way with its host, the Asian honeybee, Apis cerana, to North America, where it wreaked havoc on the European honeybee, Apis mellifera. Commercial beekeepers dumped chemicals into the hive, the mites developed resistance, and they are still a problem to this day.
The beekeeper always has an eye on the mite count. I'll never forget hearing the mite described in the first beekeeping class I took: "Imagine a mite the size of a dinner plate, attached to your shoulder, sucking your blood, weakening you, and transmitting viruses to you." That is how big they are in proportion to a bee's body size. A parasite doesn't want to kill it's host, but that is how the story is going right now. Things are out of wack for the mite and the bee. The complexities of this relationship deserve further writings, so I'll stop there for now on that subject.
|"Sticky Board" for monitoring mites. Coat with oil and slide under the hive.|
I primarily monitor mites with sticky boards. Since the bottom of my hives are screened, mites regularly fall off the bees and out of the hive. Doing a passive count over 48 hours and dividing by 2 to see how many mites drop in 24 hours is a way to get an idea of the mite load in your hive. Other methods are more accurate such as taking a measured sample of bees and either shaking them ino a jar of alcohol (which kills them) or powdered sugar (which doesn't) and then counting the mites that fall off them. These techniques are called doing an ether roll or a sugar roll. Sticky boards just give you a general idea of how many mites are likely in the hive. Mite populations spike this time of year, so I need to keep an eye on them to make sure I am sending the bees into winter without too many mites.
If I feel that I need to do something about the mites due to the number I observe, my treatment of choice is MAQS, or Mite Away Quick Strips, a product that utilizes formic acid in high concentrations. Formic acid occurs naturally in honey, though in the concentration in these strips, it can be hard on the bees. The temperature restrictions say you can use it when daytime temps are at a maximum of 85 degrees F, though I don't think I would use it over about 75 degrees. I would like to experiment with Oxalic acid and Hopguard now that those treatments are legal in the US.
Chemical treatments are still available, and commercial beekeepers generally rotate between different chemical treatments to minimize mite resistance. A sad side effect of these chemicals (besides effects on the bees) is that the global beeswax supply is now contaminated with a myriad of chemical miticides.
Mites love brood, so making splits is an effective way to break the reproductive cycle of the mites. One of the splits doesn't have a queen, so there is no brood for awhile while a new queen is reared. I have had lower mite numbers since I regularly make splits.