Finding bee colonies infested with varroa mites is every beekeeper’s worst nightmare. And if you’re facing this in reality, I can tell how anxious you are right now.
You must be wondering, how many varroa mites are too many?
After repeating the mite count process at least twice on every hive, if you find that the infestation percentage is less than 2%, no immediate action would be required. But if the percentage is higher than that, apply mite control methods as soon as possible to prevent hive death.
But I’m sure this small piece of information doesn’t answer all of your questions.
In this article, I’ll be walking you through a detailed breakdown of how much of these mites can lead to a potential colony death, as well as the methods of determining the level of infestation.
So, read along!
How Dangerous are Varroa Mites for Bee Hives? Know Your Enemy!
Before discussing how many of these mites your bee colony can tolerate, let’s first see what exactly we’re up against, shall we?
Varroa mites are scientifically called Varroa Destructors. I’m sure that this name alone is a good hint of what the whole discussion is about.
Varroa mites feed on the fat bodies of both mature bees and larvae, causing them to lose weight and overall immunity.
Not only that. The wounds these mites leave from biting the bees make them susceptible to various deadly viral infections. Out of which, the Deformed Wing Virus (DWV) is the most common.
If you’re vigilant enough, you’ll notice bees not filling outer brood frames, along with many other signs of a weakened colony. Here’s what “The Royal Society” had to say on Varroa Mites.
Varroa mites are parasites partially responsible for the world’s collapsing bee populations. Researchers have found that the #Varroa mite sucks the bee’s blood, reducing its ability to fight viruses https://t.co/Yihjw3UJHO pic.twitter.com/G3a2xCjj6y— The Royal Society (@royalsociety) April 18, 2019
If we dig a little bit into a varroa mite’s life cycle, we can see that they can double up their population within a short time span of only 10 days.
So how exactly do they cause an entire honey bee colony to die?
The life cycle of Varroa mites causes a rapid bee population drop when drone rearing stops, and these vicious mites target worker bee larvae.
Besides, within a few months of infestation, the overall colony health massively declines. They end up losing weight, getting infected with diseases, and larvae emerge with genetic impairments.
Altogether, making them lose the capacity to survive the winter. As we know during winter, bees need more energy and strength to overcome the wintering effects. So here we listed some products that can supply your hive with enough nutrition.
What is the Tolerable Varroa Mite Count?
Now, when it comes to setting a varroa mite threshold level, I must say that it varies within beekeepers.
But what I can say for sure is, no economic beekeeper would tolerate a high might count that could lead to mass colony deaths. And ultimately a huge financial loss.
If multiple new mites emerge from a single brood cell, then you can imagine how quickly the mite population increases. Especially when you consider the egg-laying capacity of a queen bee during the brooding season.
So in my opinion, if you don’t want to risk the survival of your precious honey bee colonies, you shouldn’t tolerate a mite count of more than 2%.
Here’s a varroa mite treatment chart containing my personal recommendation on the acceptable mite count.
|Mite Count Method||Tolerable Mite count (Summer))||Tolerable Mite Count (Autumn)|
|Alcohol Wash||2 mites out of 100 bees||3 mites out of 100 bees|
|Powdered Sugar Roll||2 mites out of 100 bees||3 mites out of 100 bees|
|Sticky Board||5 mites in 24 hours||7/8 mites in 24 hours|
And as the hive strength varies on different factors, like location, genetics, etc. In some cases, a total mite count of only 1000 can be fatal. So why take chances, right?
Make sure to keep a track of the mite population in every season so that it doesn’t reach an irreversible state of destruction before you even contemplate acquiring any varroa mite control methods.
Now you might be thinking, in what methods can you get an appropriate mite count.
Rest easy. Below I’ve elaborated on some of the most effective mite counting methods to help you properly estimate the mite infestation level in your colonies.
So, keep scrolling!
Most Effective Varroa Mite Counting Methods
Here are some ways of keeping track of the varroa mite population in your colonies. Also, don’t forget to suit up with bee protective gear before conducting the tests!
Alcohol Wash Method
This is unarguably the most effective method of estimating the varroa mite population in your hive. But the disadvantage to this method is that bees die in the process.
The ideal number of bees to collect for a mite counting process is 300, which you can collect using a ½ cup measuring cup.
Hold the hive board and scoop downwards using the cup, so that the bees fall into it. After your cup gets filled up with bees, put them inside a wide-mouthed jar of #8 mesh screen lid.
You can collect this equipment separately, or you can just get yourself a varroa mite test kit to get them all together.
After containing your bees, pour a 70% alcohol concentration into the jar. Make sure all the bees are submerged.
Shake vigorously for about two minutes to make sure all the mites come off from the bee’s bodies.
Then pour all the alcohol on a white plate or bowl, so that the mites are clearly visible.
Count the total number of mites and divide it by 3 to determine the percentage/ the approximate mite count present in every 100 bees.
Repeat the whole process once more to determine the accuracy of the method.
Powdered Sugar Roll Method
This method works like a varroa mite calculator and gives you an accurate mite count. Your bees won’t die when you conduct this method but may end up having injured legs or wings.
Collect bees in an #8 mesh screen lid jar in the same way mentioned in the previous method.
The only difference between this method and the alcohol wash method is that you’ll use powdered sugar here instead of alcohol liquid.
So how about checking some good quality powdered sugar within a reasonable budget? Well, here it is-
Put in about 2 tablespoons of powdered sugar through the mesh lid and shake the jar vigorously for 2 minutes. Then shake the jar on a white plate for the mites to fall on it.
Count all the mites and divide by 3 to find out the percentage. Repeat the process for determining accuracy.
Sticky Board Method
In this method, you basically determine mite infestation level through the average number of mites naturally falling every 24 hours.
The advantage of this method is that no bees are killed in the process. And the disadvantage is that it’s a comparatively lengthy process.
Insert a whiteboard under the brood chamber of your apiary, above which there’ll be a #8 mesh screen. The board must be covered in a thick layer of petroleum so that the mites can’t go back up after falling on the board.
Retrieve the board after 3 days and divide the total number of mites by 3 to find an average mite drop within 24 hours.
You can however speed up the process using oxalic acid dribble or smoking essential oils.
Visual Signs of Varroa Mite Infestation Level
There are some visual signs your bee colonies will give away when the mite infestation escalates. And you need to have a sharp eye for that.
The first thing you’ll notice is that bees will look lean due to weight loss and the hive not working productively. You may also find dead bees on the ground.
Also, look out for bright white varroa mite feces deposited inside the brood cells.
Besides, you’d be able to clearly notice signs of virus epidemic in the colonies. Such as deformed wings, paralysis, etc.
Here are some of the most regularly looked-up questions regarding varroa mite infestation in honey bee colonies.
Why am I unable to see varroa mites?
Adult varroa mites typically position and feed themselves from the abdominal area of the bees. So as these tiny insects stay hidden under the bee’s body, you’re unable to see them.
Do mite counting methods help control varroa mite population?
These methods are known to reduce 20% of the mite population. It may not be much. But it’s still considered helpful.
Can bees resist varroa mite infestation?
Yes! There are mite-resistant bee variants that can resist harm and even control mite reproduction.
We’re finally at the end of our discussion regarding how many Varroa mites are too many. I’ve tried my best to bring this ten-page worth discussion in a concise, yet well-explained manner for your convenience.
Hopefully, I could provide you with the exact information you were looking for.
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