Q Shelf Life of Oxalic Acid
I have several questions about oxalic acid (OA). How long can mixed oxalic acid used for drip be kept? How long will the crystals in an open foil pouch tightly wrapped last? (I cannot find this information on the containers.) Also, for both, if they can be kept, how should they be stored?
South Carolina, December
I passed your question to Dr. Cameron Jack who is a faculty member here at the University of Florida. He is our resident expert on oxalic acid. He has read all of the studies published on this topic to date. Here is his response:
“I would say that you do not want to mix it in water long before using it, but I do not have a lot to back that up. There is really nothing about storing OA on the EPA label. On the ApiBioxal label, we get a bit of information. They say:
“Do not refrigerate or freeze. Protect from direct sunlight. Store the powder in the original packaging. Close after use to protect from humidity. After opening the package, use within 3 months.”
Product labels, like this one, should include storage information. My recommendation is that you contact the manufacturer of the OA product you are using and ask them, especially if the information is not directly on the label. You might also check the product’s website for storage information. I will say, though, that with pesticides, it is always best to use what you mix and not mix more than you plan to use at that time.
Q Is Honey Really Sterile?
I went to a basic beginner’s beekeeping course during the startup phase of my beekeeping endeavor. There I learned that honey has antimicrobial properties and that is why it can be sold raw without needing FDA oversight. So, proudly I have been telling people that my raw local honey is safe because bees sterilize the hive and honey has antimicrobial properties. This has been all fine and well until recently … I live in the Pacific Northwest, and we all know that Asian “murder hornets” have been found in Canada and Washington. The other day, my sister sent me an article titled, “Honeybees use poop to ward off those terrifying murder hornets.” Apparently, the eastern honey bees have evolved with a skill of dotting their hive with feces they collect to defend themselves from Asian murder hornets. I thought this was interesting, so I told my husband. He said, “Well, honey, there goes the idea that honey is sterile. Nobody’s gonna wanna eat s*** honey.” The end result has been two things:
- I keep thinking about all the things bees are exposed to as they go about foraging, and I am feeling less certain about raw honey being safe to eat, and
- To keep my hives safe from murder hornets, perhaps it is a good idea to put kitty litter boxes in front of them for the neighbor cats to use as a first line of defense.
Great questions. First, the honey bee hive is definitely not sterile. All sorts of microbes call honey bee hives home. Second, honey is not completely sterile given yeast can live in it/ferment its sugars when the moisture content of honey is high. Furthermore, bacterial spores can “survive” in honey … even if only in an inactive state. That said, most microbes cannot grow and/or reproduce in honey. Most of those are even killed by honey. However, some bacteria (and other microbes) form spores, which are basically a life stage that helps the bacteria survive environmental stress. This allows them to remain dormant in honey until they are moved to a more suitable environment where they become active.
Though honey is generally viewed as a safe product to consume, it is not without risk. For example, pediatricians recommend that infants under a certain age not consume honey, given that botulism spores have been found in it (before you panic — botulism spores can be found nearly everywhere). Honey can contain contaminants as well. However, I maintain that the risk of these is quite low. In fact, the collective data suggest that honey is a safe product for consumers. I eat as much honey as my tummy allows. ☺ As a parting note, the National Honey Board is a great source of information on honey, its benefits, etc. You can check out their website at: www.honey.com.
Q Honey Bees and High Altitude
What is the elevation limit for the honey bee? I live in western Colorado and possibly have opportunity to place some colonies up in the high country at about 9,000 ft. I am interested in this because there is usually a very robust wildflower bloom up there in June and July, but I am not sure if it is a good idea! Can honey bees thrive at this altitude? Possibly higher? Would the move from 6,000 feet (where I live) to 9,000 feet be hard on them? This would only be for about three months during the middle of summer, so I would not be trying to winter them at that elevation. I cannot seem to find much information on this topic.
Cody – This is the first time I have ever been asked this question. I passed this question to two German colleagues, a husband/wife duo of world renowned honey bee research fame: Gudrun and Niko Koeniger. They have studied honey bees all over the world and at varying altitudes. Here is their response:
“We have no experience with [Apis] mellifera colonies in this height. We asked some beekeepers and heard that in the [Austrian and Swiss] Alps, beekeepers migrate their colonies on high mountains into the wildflower blooming region, probably only up to 2000 m [about 6,600 feet]. But as you also know, there are wild honey bees living in high mountains — A. mellifera monticola, A. nuluensis and Apis laboriosa. They may migrate up to 2500 m [about 8,200 feet] or even higher.”
Just for your information, Apis mellifera monticola is an African subspecies of the same species of honey bee we keep in the U.S. (we keep European-derived stocks of Apis mellifera). These bees nest up to 3,000 m [~9,850 feet] with regularity. They migrate up/down mountains in response to resource availability and environmental stress. Thus, it is possible for some varieties of A. mellifera to survive at this height (i.e., it is in the gene pool).
I did a search online and have seen reports of folks keeping bees above 8,000 feet. They talk about the challenges of keeping bees at that height, mainly because of prolonged winters and shortened production seasons. Given that you are only proposing to take them up that high during a brief period in summer, my guess is that the bees will be OK. If I were you, I would take up two or three colonies this year (just for the bloom, of course), see how they perform, bring them back after the bloom, and then determine if it is feasible to take more next year. If you end up doing this, please let me know how it goes. I will share your experiences with the readers of this column!
Q Wind turbines and Honey Bees
Sometime in the past, I read an article somewhere from a beekeeper in Europe talking about the effect of wind turbines on bees. His statement was that an electromagnetic field (or something similar) was created by the turbines that interfered with a bee’s ability to navigate and find its way back to the hive. He had made a recommendation of a distance to set hives away from the turbines but since I did not feel the need to remember, I did not.
Times have changed. This summer, 68 wind turbines have been erected and are starting to operate around me. The closest is 600-700 feet from one group of hives, with another less than a quarter mile from another yard. I am wondering what will happen to those hives.
Super timely questions, Ed. A young lady named Michelle Weschler has worked in my lab over the last couple of years. She just left my lab to go to graduate school elsewhere. Michelle happens to be developing a series of projects to answer the very questions you are asking! So, while there are no answers to this question at the moment (sorry about that), Michelle and her lab mates plan to get answers to these and other related questions imminently. Nevertheless, I did ask her input on your question. Here is what she said:
“I am only starting to review the current literature on the topic (of which there is not too much) and none of the papers my advisor has given me have explicitly mentioned honey bees. [A paper I am reading] focuses more on migrating insects and their potential to strike turbines (which is obviously less of a concern for managed honey bee colonies). The paper does, however, list several hypotheses for why insects may be attracted to wind turbines, none of which include electromagnetic fields. The only mention of electromagnetic fields I found was in relation to the cabling connecting offshore wind turbines and their potential effect on marine life, an “understudied field of research” as it were. I do not know a lot about electromagnetic fields, but it seems like their effect on terrestrial species is potentially mitigated by the cables being buried. As alternative energy options continue to be developed and built, I do not doubt [that] we will see more studies about this very topic.”
So there you have it. I did happen to find reference to a study in Poland where the conclusion was that windfarms have no impacts on honey bees. However, it is only one study and I am sure it needs to be repeated in scope and geographically. I agree with Michelle, though, in that people are going to be looking at the effects of wind turbines on nearly everything now that their popularity is growing.
Q Requeening and Pollen Patties
Last season was my first bee season. I did not have any success with colonies requeening themselves. Twice this past season, I had colonies that I left to requeen themselves, both times failed. I will try again next season, but am beginning to wonder: Is it possible that I do not have a …