Interview With the Canadian Scientist Who Discovered That Balsam Fir Needles Kill Lyme Disease Causing Ticks

So what I'd like to do is ask you about how you determined that balsam fir needles could kill ticks, and in particular, why does it seem to only work or work better under very cold temperature conditions?

So what I had noticed, and this is sort of the way science works, is observation. And I know that's why citizen science can be so powerful: You've got lots of people observing. So I was observing, and I just noticed that I didn't see a lot of ticks coming out in the early spring, where there were a lot of balsam fir trees. And it was just a hunch, and so I thought, "Well, let me see." So I brought in ticks, into the lab, and then we also had balsam fir needles, and we chopped them up, and we put them in an incubator. So it was a winter-like condition for the ticks, and they died. It took a long time to kill them, though, so it didn't kill them right away. It took a few weeks for them to be sitting in balsam fir before they died. So then I thought, "Well, I wonder if I could make this more powerful."

I was working with my colleague, Nicoletta Faraone, at Acadia University, who's a chemist, and we distilled the essential oil out of the balsam fir needles. And when I used balsam fir oil, that was a lot more lethal. Now, the problem with essential oils, as probably people know, is that they evaporate, and so at warm temperatures, they disappear. So it still takes a while to kill ticks. So essential oils, particularly at the low percentages I wanted to use, because I was thinking ahead. And I know one of the questions you're going to ask is, "Where is this going?" I wanted to make sure this wasn't going to be lethal to other organisms, or as low lethality as I could get. So I was using very small percentages, and because of the small percentages, I needed cold temperatures, so that the essential oil would last long enough to have this slow effect on the ticks; they would slowly die. And it turns out to be amazingly effective, and that's what we found.

So what we did was we just had the ticks in these little cotton balls, and they were each one tick per tube, and we put them in incubators to simulate winter temperatures, and we added small amounts of balsam fir essential oil, and that was in the paper. And we found that as long as the temperatures were cold, we could get 100% lethality, but if the temperatures were warm ... I'm going to use Celsius, but feel free to change that to Fahrenheit for yourselves. If it's above 12 degrees Celsius, it hardly worked at all, and it had its best effect if temperature stayed below four degrees Celsius. So we're looking at 36, 38 degrees Fahrenheit below that.

So what are the next steps for the study?

Well, so the study is now complete, and I published those results. So what we're working on now is something a little new for me, at least, is I would like to have a practical application to this. And ideally, what we're working on right now is: Can we turn this into as low-toxicity product as we can, so that people could put it on their yards, for example? And over the winter, it would slowly get rid of all the ticks.

Now, there are a couple things we need to do. We realized very quickly that one, I wanted something non-toxic, so we're only using food-grade ingredients, so literally, stuff you can eat. And also, we wanted to use very small percentages, so that we wouldn't have toxicity on other organisms. And we needed to get into the leaf litter for this to be practically useful to people. Because maybe you don't know: How do ticks get through the winter? They burrow into the leaf litter, and it's like an insulating blanket. I don't know if you had there, where you are, but we had some very cold weather recently. It went down to minus 20 Celsius, very cold. You would think all the ticks would be dead, because they're not actually cold-loving arthropods.

But it turns out, probably not, because we had sensors. Laura Ferguson, who's another colleague of mine, Acadia, we have sensors in the leaf litter, and it only went down to minus five Celsius, which ticks can handle. So that's why ticks can get through the winter. So if we want to get those ticks, we have to make sure the balsam fir can go through the leaf litter and find them where they're sleeping, basically.

And so that is our goal right now, and of course, we don't want to use petroleum products, and we want to use literally, just food-grade materials. And I think we can do it, and we've got a handle on it, but we need to perfect it. So that's one thing.

The other thing we're doing is we need to ensure this has minimal toxicity and is ecologically safe, so we're looking at off-target effects. Fortunately for us, most of the pollinators are not out at the wintertime, and very few of them are in the leaf litter where the ticks are. But we do need to do our due diligence, so that takes some time, and that's what we're working on now.

I mean, that's the aspect of your work that I find most intriguing, is the idea that this provides an opportunity to apply an acaricide, something that can kill ticks, during the winter season. You talked about how the ticks can overwinter, because they're hiding under the leaf litter. I know from my own research experience that if you don't want the ticks to move around much, if you're using them in the context of a mouse infection study, you keep them on ice.

But my own observation this winter, living here in Danbury, Connecticut, is that we've had some relatively warm days, and I've unfortunately had to pull ticks off of myself and off of my dogs that are playing around in the back yard, because the ticks become active again. And that's something that's very unusual. I think it is a reflection of the warming winters and the shorter time period that the ticks are subjected to very cold weather.

It's also a function of the way ticks overwinter. Ticks are not insects, so I'll say arthropods. Many arthropods that overwinter, they go into what's called a winter diapause, and they are truly hibernating. So even if there's little warm bumps in the winter, they tend not to wake up, because their bodies are physiologically changed. They've pumped themselves full of antifreeze proteins, and they're just waiting.

Ticks do not do that; they just lightly slumber. You can see; that's from their southern heritage. They didn't evolve in Connecticut; they evolved further south. And they keep some of those traits, and you would think that that would make them susceptible to cold, and if they didn't hide under the leaf litter or wood. But what it does mean is they are opportunistic. So as soon as temperatures go above ... I'm trying to convert in my head. About four degrees Celsius. It's got to be 40 degrees or so.

32 degrees Fahrenheit, yes.

Yeah, they wake up. It's easy for them to wake up, because they haven't switched their whole physiology. They're in a light behavioral quiescent state, but it's not a true diapause. So that's why whenever winter temperatures get warm, and they're desperate at that point, especially the adults. So the adult ticks that are overwintering are adult ticks that couldn't find a host in the fall, and they're looking hard. They would rather not get you. They'd rather get a deer, because they're looking for mates, as well. They're probably not going to find a mate on you.

Hopefully not.

Hopefully not. That suggests you have many ticks, which would not be good. So that is a good point to remind people, that with these warming winters, you will see ticks as soon as it's warm enough for them to move, and it doesn't require very much.

So the other question I have is related to the fact that this is an essential oil product, and again, from my own personal experience, I contacted my tick control company, and unfortunately, they informed me that they do not do spraying for ticks during the wintertime.

So do you think that this essential oil product, if it's ultimately commercialized and made available to the public, is it something that a homeowner would be able to apply themselves?

I would say yes, but I think probably would be better to let a professional, because they have the high-powered nozzles, which will help these products get into the leaf litter. It's just because of where they are, and they have the specialized equipment, and that combined with, I hope, the formulation we're developing, which helps drag it down below the leaf litter, between the two, would probably give you good coverage. No, I think winter is overlooked. Let's say an overlooked season for control. I think it's got a lot of potential. These animals are not moving around very much, which means you have a good chance, once you've saturated an area, that they'll stay there and let this low-toxicity product slowly kill them.

The other thing about it is that there aren't very many other organisms around, so it can really reduce off-target effects, and the last point is it's a vulnerable time for ticks. They actually don't like winter very much. As I said, they're in this behaviorally quiescent state, but they're not comfortable in the winter, and it's a stress for them. So if you start piling stressor upon stressor, you can really increase the lethality. And so unlike maybe some of our native insects, they're more susceptible, and I think more fragile, at this point of time, point of the season. And I think it's been overlooked as a method of control.

Okay, I've got one other question that unfortunately, is going to demonstrate my ignorance of chemistry. But the other intriguing idea for me is with an essential oil, it's an oil; it's maybe not as dissolvable in water. So do you think that once applied, the essential oil from balsam fir needles would remain longer in or under the leaf litter, even if you get a rain in the winter? That it wouldn't necessarily wash it away as readily as in the summertime?

So what we found is that just plain old balsam fir needles themselves do not really control ticks in the real-world situation very well. The reason I was seeing it, it's my self-observation, is because this was right under a balsam fir tree, and all the leaf litter was balsam fir. But typically, you have a mix, and they will move around. They will search. Ticks will move around for their favorite overwintering site, so they will not actually overwinter under balsam fir needles, if that's all there is. They'll move around until they can find their nice maple, oak, comfortable, cozy leaf litter.

So what we're doing with our formulation is trying to solve exactly that problem. We're going to encapsulate. Basically, we're working on encapsulating the balsam fir into little basically food-grade capsules that will get into the leaf litter and slowly dissolve, and so they will stay there. That's what we need to test, is making sure that with massive rain and snow melt, it won't all get lost in the runoff, and that is something that we need to test.

I have some hope, just because of the type of capsules might stick to some of the leaf litter and so may not be washed away with the rain, because our winters are becoming, well, at least here in Nova Scotia, wet, because we're going through these cycles.

Same here.

And these cycles, it's not just rain, but snow melt. And so it's something that we have to consider, and we are on it, but it's one of the reasons it's a difficult problem, and we are working on it.

Right, right. Well, no, what you've just related is absolutely brilliant. It's the tick-control equivalent of a time-release capsule that we might take, as humans, to treat some condition.

Yeah, yes.

Well, that's wonderful. I really appreciate your taking the time to tell us more about your fascinating research.

Happy to do it.  Just wish us luck for our success. We're trying to come up with something as non-toxic and cheap as possible, so that everyone will have, I hope, reduced experience with ticks and Lyme.

Yes, you will be able to count me as a customer.

Thank you very much.

All right, have a good day.

You, too.

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