Sustainability, Sustainable Lifestyle

Bti: An Easy, Natural Way to Stay Mosquito Free

Are you a mosquito magnet? I know I am. Since my Graduate Assistant position has me out and about during peak bug biting hours, I spend all summer itchy and covered in welts. I could use bug spray, but I don’t like the idea of DEET and the organic lotions don’t seem to work very well for me. It’s not fun, but there’s hope. Even if I can’t avoid them at work, the Llama found an amazing solution for around the house. It’s called Bti, and it’s an all natural solution that kills mosquitoes, but leaves everything else alone. Seem too good to be true? I know, I was skeptic too, but read on before you make up your mind. I think you’ll be pleasantly surprised.


What is Bti?

Bti stands for Bacillus thuringiensis isrealensis and is a naturally occurring bacteria found in soil and water around the world. It was first discovered in 1976 by two researchers, Goldberg and Margalit who managed to isolate the bacteria from dead mosquito larvae they found in Israel. Since then, Bti has been used as a natural pesticide for mosquitoes and has proven to be highly effective at reducing mosquito populations in an area.


How does it work?

Bti products contain non-viable bacteria spores and an endotoxin produced by the bacteria. The toxins are nontoxic to all living things except mosquitoes and other the other pest insects classified as “true flies.” When the mosquito larvae ingests the toxin, the chemicals in their stomach linings reacts with endotoxin and kills them before they can emerge as adults. Bti can be effective in two to twenty four hours. Taking out the larvae is great, because they can’t grow up to bite or reproduce! Furthermore, the bacteria breaks down quickly and moves out of the environment, so mosquitoes will have less of a chance to build up resistance to it.




So it won’t kill anything but mosquitoes?

Yes! Well, mostly yes. It will affect other “true flies” like horse flies and houseflies. “True flies” tend to be pest species as well, so you may not mind a few less of them hanging around. If killing anything but mosquitoes are a concern for you, keep in mind that most of these species don’t lay their eggs in water and won’t come in contact with toxin. Once you’re outside of the fly family, it’s virtually harmless. Other creatures don’t have the right chemicals composition in their stomachs to activate the endotoxins.

Let me give you an idea of how minimal the risk are with Bti. We learned in my Master Gardener class (read about Master Gardening here) that a human would have to ingest about 1 pound of Bti per 35 pounds of body weight to before you’d get close to a lethal dose. In comparison, it would take you .08 pounds of caffeine per 35 pounds of body weight before you got to the same point. Bti is less toxic than your morning cup of coffee. Chemistry aside, you can rest easy adding Bti to water that comes in contact with other organisms. It will only hurt the mosquitoes.


Bti sounds great. Are there any downsides?

Depending on where you live, you may need to use additional methods to control mosquito outbreaks around your home. Small pools of stagnant water are easy to treat, but you may be out of luck if you live near a marsh or still lake. Also, you’ll need to make sure that you reapply Bti accordingly to keep it active. Once mosquitoes move past the larval stage of their life cycle, the bacteria no longer affect them.




How do you apply it?

Applying Bti is simple. Usually all you need to do is dissolve some of the bacteria in standing pools of water, though make sure that you follow the directions on the package of your chosen product. If you want to take your pest control further, you can build your own mosquito traps. Mix water and Bti in a small bucket like this one, add a stick that pokes out over the water to allow the insect to lay eggs more easily, and place it wherever you’ve had insect problems in the past.


What product should I purchase?

There several Bti products on the market, but we particularly like Mosquito Dunks. They’re easy to use and work great!


Here are my sources. Happy reading!


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