# Rhubarb Leaves control mites?



## AR1 (Feb 5, 2017)

I was reading the Wikipedia article on rhubarb (cut mine today and made sauce) and there is a little note deep in the article that says some people use rhubarb leaves in their hives to control mites. Rhubarb leaves are a natural source of oxalic acid. This seems a little iffy, no way to know how much oxalic acid is in a particular leaf, so how much to use and for how long? Still, interesting. Anyone try this?

...Rhubarb leaves can be used in honey bee colonies as a mild Varroa-cide, either as crushed leaves or in the form of a tea. Rhubarb tea soaked paper towels/shop towels or crushed leaves are placed above the broodnest. Worker bees immediately begin removing this foreign substance, exposing the colony to oxalic acid in the process. Oxalic acid is toxic to Varroa mites, and mite drops increase while these rhubarb remedies are on the hive. https://en.wikipedia.org/wiki/Rhubarb


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## Michael Bush (Aug 2, 2002)

I'm sure there is not enough oxalic acid in rhubarb leaves to cause the Varroa mites any discomfort at all. Nor the bees, for that matter.


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## FlowerPlanter (Aug 3, 2011)

Someone post the same question a month or so ago. Can't seem to find the thread. 

There's about 0.5% OA in rhubarb leaves, you would need around five pounds of leaves to treat a hive. Can't imagine even the strongest hive chewing a pound of leaves, a half of a percent of AO may be way to diluted to do much. R Oliver's shop towel is >30% AO. 

http://scientificbeekeeping.com/oxalic-shop-towel-updates/

There are a lot of veggies that have the same or more percent AO than rhubarb leaves. Rhubarb leaves don't sound so toxic when you compare them to a carrot.

https://www.ars.usda.gov/northeast-...s/oxalic-acid-content-of-selected-vegetables/


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