Much Ado About Mites: Making Decisions for How to Address Varroa Mites in Hives

Written by Mandy Shaw of Waggle Works

Photo by Lisa Dillon Photography
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Whether we like it or not, our bees have mites. Deciding what to do about it can be challenging, confusing, and sometimes discouraging.

If you are like me, you want to keep your hives as naturally as possible. After all, bees in the wild survive without human intervention so ours should be able to, too!

I recently attended a seminar hosted by Dr. Thomas Seeley, and he raised some really important points to consider: Wild colonies are generally living in small cavities which promotes swarming and small brood nests. Swarming is really important because it creates a break in the brood cycle which interrupts the Varroa’s brood cycle, too. He conducted studies comparing hive sizes in managed apiaries, and the results were astounding! The colonies kept in small hives (in this study 1 langstroth deep) had more frequent swarms, yet their Varroa numbers were lower, and their winter survival rates were higher. The large hives in the study (2 deeps & 2 supers) had fewer swarms, higher mite counts, and lower winter survival rates. The only benefit to the larger hives studies was surplus honey. He also said that if he wants to get a honey crop from his bees, he knows that he will need to treat his colonies for mites. This year I am experimenting with keeping smaller colonies in my own apiaries!

Another point of consideration is your location. In densely bee populated areas, the chance of your bees coming into contact with a Varroa infested hive is real and should not be ignored. When bees rob a failing colony, you can be certain that they are bringing home mites. If you have a colony that is showing symptoms of VMS (varroa mite syndrome) and you do not plan on treating or euthanizing the colony, using a simple robbing screen can help prevent the spread of mites to other colonies.

We all want varroa sensitive hygienic bees! The truth is that not all bees have this trait. In our mission to allow the bees to evolve to become genetically proactive about mites in the hive, we are compromising our goal by bringing bees from other regions into our area. Consider catching swarms and purchasing your bees locally!

When you are keeping several hives in the same yard, try spreading them out to reduce commingling. Ideally, a distance of 15-20 feet. In our urban backyards this isn’t always possible, so another suggestion is giving each hive its own distinct appearance to help the returning foragers and drones better recognize their home address.

Propolis is another element of overall colony health which can help the bees fight the viruses that Varroa mites spread. You can encourage propolisation in your hives by scratching up the inner surfaces with a steel brush or nail heads. When bees live in tree cavities, they coat every surface with propolis. The insides of our hive walls are generally smooth, so by roughing them up you will be encouraging your bees to make them smooth again with the use of propolis!

Drone with Varroa Mite, Photo by Sepp Shaw

A natural method to discourage Varroa infestations is simply removing excess drone brood (but not all of it, because we need drones). As we know, drones have a longer pupation which allows the mites to raise even more mites.

Good nutrition is key to helping our bees have healthy immune systems. Varroa can have devastating effects on honey bee immune systems, so making sure they have enough quality food available will help their immunity. If you need to, supplement their diet with sugar syrup and or pollen patties.

Screened bottom boards can help to give the mites a space to go when they fall off of the bees. Be sure that the SBB insert is greasy so the mites will stick to it, and clean it often!

Making a split from a strong colony in the spring & summer can create a natural brood break. Another way to induce a brood break is to cage the queen (in a special cage that still allows the workers to access her) for a period of 14-21 days. You can read more about that on the Portland Urban Beekeepers blog.

The number one recommended defense against mites is to be proactive in monitoring your colonies! Ideally, you would check your colony for mites in the spring, and then again right after the nectar flow so that you have time to take necessary action, then again before your bees begin transitioning into fall. If you are not sure how to sample your colony for mites or need help recognising when a colony has too many mites, check out the Honey Bee Health Coalition’s Tools for Varroa Management. It is a free downloadable PDF that gives instructions on sampling, what the results mean, and a breakdown of all of the treatments on the market.

Mites are not something to be ignored and are a part of keeping bees that we need to be comfortable understanding and addressing.

Questions? Give Bee Built a buzz or contact me at waggleworkspdx@gmail.com