- Author: Kathy Keatley Garvey
The honey bee guru continues to answer a range of questions. The latest concerns the effect of marijuana growing sites on honey bees.
We thought we'd share his answer, which deals with honey bees, pollinators, Cannabis, pesticides, and what could happen to beekeepers who stumble upon a pot farm.
The question: "What is the effect, good or bad, that marijuana plants and marijuana grow sites have on the honey bee? From what I understand, these grow sites are using chemicals to control pests year round. In some cases, I hear that marijuana growers are importing chemicals from Mexico that are stronger and work better to control pest."
Mussen answered the question succinctly and openly.
"As you might guess, since marijuana is still considered an illegal plant to grow by the federal government," he replied, "it is no surprise that there are no pesticides registered for use on the 'crop.' Some states are trying hard to build a list of acceptable products, but here is the problem. So far we have registered products based on contact and oral toxicities to mammals. We have only run inhalation toxicities on a few very potent and stinky products (fumigants). You can get up to 10X the dose of a chemical, from the same amount of plant mass, if you smoke it versus eating it.
"There are quite a number of websites dedicated to pot growing. When pest control becomes the topic, most sites suggest mechanical methods or use of products allowed in organic agriculture. However, those organic pesticides have not been checked for inhalation effects, either."
"Thus, practically any pesticide that is used will be illegal. Given that, growers are apt to determine which materials work best on the pest at hand on other crops, acquire those materials, and use them. The regulators know this, and in states where marijuana currently is legal, the states are testing some of the products on the shelves to see what pesticides are in them. The samples have been found to be pretty clean, for the most part."
Mussen acknowledged that blooming hemp plants are attractive to many pollinators. "I have no idea what the pollen and nectar might do to them when the bees consume it. We can provide a pretty good idea of what will happen when pesticide products used on other crops are applied to the bloom (at agricultural rates), but since nothing is registered, there is no way of guessing what might be used. For the standard fee of just under $400, we can send a sample of the bees or pollen to the USDA AMS pesticide residue detection lab in Gastonia, N.C., and they can tell us the residues. Butthat doesn't help us much in terms of regulatory assistance.
"Pot growers probably won't care if they repel or kill visiting bees," Mussen speculated. "Pollinated blossoms become senescent too quickly, and do not produce the maximum amount of important resins if they are pollinated early in their cycle."
"Up to this time, I have not heard of beekeepers reporting damage from pesticides applied to marijuana, but it is likely to happen before long. Beekeepers are more worried about being shot if they accidentally get too close to a pot farm."
Stay tuned.
Don't get me wrong -- pesticides used on cannabis is certainly an issue worth exploring, especially as medical and recreational legalization continues to spread across the country, and the size of pot growing operations increases. So I don't blame Mussen for wanting to draw attention to the issue. But it's really unfortunate that he apparently didn't consult with anyone with even some basic knowledge of how cannabis is actually grown.
For the reasons stated above, the chances of cannabis pollen becoming any kind of significant source of nutrition for any hive of honey bees seems extremely low, if not practically nonexistent. As far as the reference to the risk of them collecting nectar from cannabis plants, I'm not sure that female cannabis plants even produce any nectar at all (and I was under the impression that they didn't). After all, they're not trying to attract pollinators, since, again, it's a wind-pollinated plant.
As a beekeeper who formerly managed around 40-50 hives in Humboldt County CA (perhaps the most famous pot-growing region of the country) and who taught beekeeping at Humboldt State University for a number of years, I have often joked that I might be the only beekeeping instructor in the country for which one of the most frequently asked questions on day one was "do I have to worry about my honey bees ruining my neighbors' pot crops by pollinating them and making them go to seed?" The answer, of course, is no. Not an insect pollinated plant.
I will just end with one intriguing thought. The one resource a mature female cannabis plant may offer to bees is the resin itself (which is what contains most of the cannabinoids). I did have a fair number of anecdotal reports of bees collecting some of this resin in September and October to incorporate in their propolis as they seal up the hive for winter (no reports of hives appearing to have suffered any as a result, but again, this is all anecdotal). If so, it could be very interesting to test the propolis in hives situated in big pot-growing areas to see whether this propolis contains significant amounts of cannabinoids. Who knows, pot propolis could turn out to be a novel and potentially valuable form of medicinal cannabis, especially considering that propolis itself has useful medicinal properties. Conversely, if bees are in any danger from either some compound created by the cannabis plants themselves, or any pesticides that might be used on them, it seems to me that the bees' collection of propolis (assuming the anecdotal reports are accurate and they do collect cannabis resin for that purpose) would be the most likely route for them to be exposed.
Keep up the awesome work!