October in the Apiary

A big thanks to club member Kate Riding for her first contribution to our "In the Apiary Notes"! Kate has chosen to share some seasonal info on varroa mitigation:

Fall Mite Treatments

            We all want to be prepared to face the onslaught of winter.  But how do we do it?  One of the common ways is to knock down Varroa mite numbers before winter settles in.  Using miticides is a popular way to do this.  Oxalic acid and Formic acid are the ones that work most efficiently.  There are different ways to use these acids:

            Oxalic acid can be used in two* ways: Sublimation, or the Dribble method.  The sublimation is the most used and widely accepted way to treat with oxalic acid, though the dribble method is becoming more popular.  Sublimation is a process in which a solid becomes so hot that it skips becoming a liquid and goes straight to a gaseous state.  When the acid is heated with a battery and sublimation plate, the oxalic acid takes on a vapor form and then forms crystals that cling to the bees, frames and mites.  The crystals have little effect on adult bees, some possible killing of brood, but are deadly to the mites.  Within 10 minutes of taking the plate out of the hive, it is safe to work, and breathe the air again.  With the sublimation there is no need to break any propolis seals and it keeps the brood temperature relatively the same.  The sublimation method of treating with oxalic acid is a slower but more effective way of treating for mites and knocking those numbers down.  

            When you just happen to mix 600 mL of hot water, 600 grams of sugar and 35 grams of oxalic acid, then take 50 mL of the solution and dribble it on your brood nest, it becomes the dribble method of oxalic acid.  The Dribble is much easier for backyard beekeepers because it does not require the storage of the battery and sublimation plate.  It works best if the bees are fed with sugar water before the treatment, so the bees are full and won’t eat the treatment.  It is also faster to do because it doesn’t take 15 minutes like the sublimation requires.  There are some requirements, it needs to be within 35-55 degrees Fahrenheit or it won’t work. There can’t be more than 5 mL per ‘seam’ and no more than 50 mL per hive. But there are some setbacks as well, there are higher brood and queen mortality rates and it is limited to an annual treatment, instead of as needed with the sublimation method.  If some of the treatment lands on the frames then it won’t get used and dispersed throughout the hive.  The dribble method has been approved by the Oregon Department of Agriculture (ODA) for the use of backyard beekeepers.  The dribble method is becoming more popular for its simplicity and the lack of experience needed.   

Oxalic acid has one major downfall.  It only affects phoretic mites and not mites in the sealed brood.  It is best used in the winter period when there is little to no brood.  Oxalic acid is one of the best options for fall mite treatment. 

Formic acid comes in treatment form as Mite Away Quick Strips (MAQS) making it easy to handle and treat.  The MAQS can be used while the honey super is still on the hive, making it even easier to rid your hive of pesky intruders.  Formic acid is the only miticide that can get both the phoretic mites and the ones inside the capped brood, which is super useful to follow up on an oxalic acid treatment.  When treating with MAQS, try to disturb the hive as little as possible.  It is okay to feed with an entrance feeder because it doesn’t disturb the colony. MAQS have been popular for several years, mainly supported by a packaging and shelf life change that took place in 2011, when they changed from Mite-Away 2 to MAQS.  The change made the MAQS safer to handle and easier to use.  One of the drawbacks of MAQS is the temperature that the acid no longer works. If it is over 85 degrees Fahrenheit the treatment can cause excessive bee kill.  Formic acid has become one of the most popular ways to treat Varroa mites, both in the summertime when you have supers, and in the fall time as a follow up treatment.

  In the fall, when the Varroa Destructor strikes, you and your hives need to be prepared.  A very popular way to do this is treating with Oxalic or Formic acid.  You can choose between sublimation, dribble or diffusion through strips.  When we have so few options to work with we might as well be informed about them.

*There is one more method, the paper towel method, which has not been approved for use on honey bees.

No matter the method, remember to follow the directions.


  1.  Shearer Turton, Bee Culture magazine, Comparing Mite Treatments  https://www.beeculture.com/comparing-mite-treatments/
  2. Emily Scott, Adventures in bee land’s blog, Oxalic acid sublimation demo, https://adventuresinbeeland.com/2017/01/22/oxalic-acid-sublimation-demo/
  3. Rusti Burlew, Honey Bee Suite, How to apply an Oxalic acid Dribble,  https://honeybeesuite.com/how-to-apply-an-oxalic-acid-dribble/
  4. Varroa Mite Controls Methods externalfile:drive-8a20857450fca323c8eb6f7b016b7edfb896ff3a/root/Varroa Mite Control Methods.pdf
  5. Randy Oliver, ScientificBekeeping.com, Oxalic acid Dribble and sublimation update, http://scientificbeekeeping.com/oxalic-dribble-tips/
  6. Nature's Own Design apiary products, Mite Away Quick Strips, Frequently Asked Questions, http://nodglobal.com/faq-maqs/
  7. Jennifer Berry, Bee Culture Magazine, Oxalic. A better way? https://www.beeculture.com/oxalic-better-way/
-Kate Riding 2018

Thank you Kate! So...now that Summer is officially over...what are your plans?? In the apiary, now is the time to finish the winter preparation!

Your hives are on the finishing end of creating winter bees and food storage.  If you have any weak colonies, they won’t be getting any better this Fall.  You should consider combining weak colonies to create a stronger colony.  This can be done either using the newspaper method after removing one queen, or just putting them together and let them figure out which one will succeed.  I’d recommend against combining a weak colony into a strong one.  Do you really know why the weak one is weak? Maybe consider overwintering in a nucleus colony...

If your mite levels are still too high (my number is 2% this time of year), there is still time for treatment.  Remember, this time of year, the bee population is dropping and the mite population isn’t and this exacerbates the mite level through the winter and into the spring.  See above for Kate's excellently compiled advice, as well as the Honey bee healthy coalition for treatment suggestions and methods. Remember to count your mites first to determine if you need to treat, and if possible, count afterward to assess the efficacy of the treatment.

Since the days are getting colder and shorter, and there are fewer plants blooming and providing less nectar, the bees can no longer get sufficient food stores.  Check each hive, either during an inspection (preferable), or by hefting the hive (not as accurate, but better if we get a cold snap.)  The hive should have at least 60 lbs of stores.  If your hives are light, you can still feed them through the middle of the month or so.  I generally feed 3 to 1 syrup this time of year.  After the middle of the month, emergency feeding can be done with dry sugar or a fondant cake placed on the inner cover.

This is also the time to finish up your winterization.  How much you do is up to you and no amount is right or wrong.  Toward the end of the month, you won’t want to open up the hives, unless in an emergency, as they will break their cluster on a cold day/night and the propolis seals between parts will be compromised.  There are two schools of thoughts on winterization:  Minimal and intensive.

Intensive involves putting a fiber mat or blanket above the hive body to absorb moisture and reduce open spaces in the hive.  The hive can be insulated by wrapping with tar paper, bubble wrap, straw or rigid foam.  Make sure you leave the entrance open as the bees will still need to go outside on warm days to eliminate and look for water.  Some folks like to include an upper entrance/ventilation hole at the upper part of the hive facing the front.  Many folks like to surround the hive, on the back and sides with straw bales or a plywood wind break, to reduce the wind.  The hive should be level or SLIGHTLY tipped forward so any condensation will drip out the front entrance and not puddle inside in the back.  A mouse guard (perforated metal) or entrance reducer will reduce the likelihood of an unwelcome mouse visitor and a rock on the outer cover will reduce the chance of it blowing off during a storm.

Minimal involves making sure there is enough food, a rock on the lid, and tilted slightly forward.

Finally, if you had an awesome summer season with many supers full of honey, you’ll want to finish your honey extraction and processing before it gets too cold (remember the old adage about molasses in January).

-Allen Engle

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