Winter Bee Mites Treatment - Oxalic Acid Dribble

Varroa mite on a nurse bee

Warm winters are hard on honey bee hives. Instead of staying clustered, honey bees send out foragers any time the weather is warm enough for flight. This reduces the life span of the winter bees and quickly uses up colony resources. The colony might end up raising brood well into late fall and winter to replace foragers.

A prolonged and mild winter can play havoc with the varroa mite numbers within a honey bee colony.

The last few winters in Northwest Ohio came hard and fast. We did not get a reprieve until Spring time. This year, I had the perfect opportunity to try Randy Oliver's (Scientific Beekeeping) recommended winter mite treatment - an oxalic acid dribble.

I read through his power point presentation. Then I used the Oxalic Acid Treatment Table and made the 1 L batch that treats about 20 colonies. I used a handheld 2 gallon sprayer
(shown on left).

Handheld sprayer for bee mite treatment -
oxalic acid dribble

At the lowest setting, my sprayer dispenses about 2.5 ml per "pass". I made 2 passes per seam of bees. I also did not treat with more than 50 ml per hive, since Randy mentioned in his presentation that Europeans recommend not applying more than that due to the colder and longer winters.

It took us about 1 hour to treat 9 hives. We should be able to see the effect in the Spring.

Changes to my Candy Board Recipe for Winter Feeding

Modified bee candy board with a diagonal rib
to stabilize the sugar block

It is the time of the year when I like to make sure my honey bee hives have plenty of resources for the winter. Even though I check their resources continually through the late summer, this time of the year I provide insurance in the form of sugar blocks.

In past years, I was able to put the blocks on in late October or early November. This year, in part due to El Nino, flying weather is extending well into December. In fact, next week still has highs well into the 50s and 60s. Yep, it is still flying weather even though it is December.

Sugar blocks are a little bit tricky to put on in this kind of weather. I want the bees to think of them as surplus and not as “flow”. For that purpose, this year I am skipping the pollen/patty part of my recipe. I am also adding a diagonal “rib” to my sugar block board that will stabilize the sugar block and prevent it from crumbling due to the temperature swings. You can see the “rib” on the picture.

Finally, in order to make the sugar brick harder, I reduced the sugar in the final phase of the quick-set method from 15 lbs. to 10 lbs. It makes the mixture set slower and as a result, the brick is more uniform.

Here is my updated recipe (original recipe is here):

Candy Board Recipe for Winter Feeding 

Equipment needed:

• Pot (I use a 21.5 quarts canning pot)
• Drill with metal plaster stirrer attachment (optional UNLESS you use the quick-set method)
• Cooking or candy thermometer
• Scale
• Gloves
• Bee candy board forms | bee fondant forms
• A wooden spoon | spatula to fill the forms and pat the mixture into shape

Ingredients needed:

• 4 parts by weight sugar (I start with 15 lbs.)
• 1 part by weight water (3 lbs. and 12 oz.)
• 1/4 tsp. vinegar for each pound of sugar (1 Tbsp. and 3/4 tsp.)
• Additional ingredients for the quick-set method:
• 2 2/3 parts by weight sugar (I use 10 lbs.)

Preparation

1. Mix together 4 parts sugar, 1 part water and the vinegar into the pot and set it on high.
2. Once the mixture starts boiling, start checking the temperature. We are aiming for the soft-ball candy stage or 242F.
3. You are done once the mixture reaches 242F. Turn off the heat. The mixture is ready to pour when it cools down to about 180F.
4. If you don't want to wait, you can proceed with the quick-set method:
5. Make sure you have your power stirrer, your spoon | spatula, your forms, your gloves and the extra sugar set out.
6. Dump the extra sugar into the mixture, mix it thoroughly and let it cook for about a minute. Spread it into the forms.