The Carnivorous Plant FAQ v. 11.5
- courtesy of -
The International Carnivorous Plant Society

Q: Are mosquitoes in my trays a problem?

Utricularia aurea
Utricularia aurea
A: Since our beloved carnivorous plants are often most easily cultivated in big trays of water, we can run into a problem.

Female mosquitoes can find their way to our trays and lay their eggs. If this happens, you will notice the little mosquito larvae (sometimes called "wrigglers") flitting about in the water. They are remarkable organisms, these little aquatics are. Have you ever tried swimming the way they do? I have. I haven't gotten the method down, but it is worth trying, if for no other reason than to amuse your friends.

All that aside, it is absolutely imperative that you prevent mosquitoes from reproducing in your water-filled trays. The mosquito larvae have no affects upon your plants, but the females suck blood from animals (including humans). Most mosquito bites are merely annoying, but some mosquitoes transmit life-threatening diseases.

Even if you are so misanthropic as to not care a rat's bum about the human species (and on some days I can understand your sentiments), have some pity for our natural world. For example, West Nile Virus is killing the birds in North America at a terrible rate, and is transmitted by mosquitoes.

Water-filled tray
Breeding ground
So what should you do? I present a few options---choose which makes sense. Some options work if you have big trays of water for storing water, or for growing aquatic species such as Utricularia or Aldrovanda. Other options make more sense if the mosquitoes are in the water-filled trays that you grow your Sarracenia in.

Drain the damned tray: Whenever you see larvae in the trays, just dump out the water! Rinse the tray quickly to remove any eggs that may be sticking to the edges of the tray. Refill the tray with water, and resume your life.

Filter the tray-water: This is my favorite choice, since I value purified water. I pull all the plants out of the tray, then slowly dump the tray water into a big Sarracenia pot in another tray. The water drains through the soil and vents through the bottom of the pot. Meanwhile, any larvae and eggs are stranded on the soil surface and rapidly perish.

Use an exclusion mesh: Fine mesh, such as available in fabric stores, can be fashioned into a cover for your tray. Make sure the mesh is very fine. This will exclude mommy mosquito from reaching the water surface. Also, even if mommy mosquito manages to make its way into the tray and lay eggs, the hatchlings will be unable to escape.

Bt toxin: A little bit of the stuff, added to the water, kills mosquito larvae and in my experience does not hurt Utricularia or Aldrovanda. Sorry, but I do not have dosage suggestions.

Include predators: Unfortunately, growing aquatic carnivores such as Utricularia or Aldrovanda does not appear to be effective. You may consider including Gambusia (mosquito-fish) to eat the bugs, but I have no experience in this realm.

Page citations: Rice, B.A. 2006a; personal observation.

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Revised: April 2008
©Barry Rice, 2005