Tag Archives: larvae

Eliminate mosquitoes by eliminating stagnant water

The most effective, cheapest way to control mosquitoes is to eliminate the standing water that larvae need to develop. A dry yard doesn’t have mosquitoes. It’s really that simple. Below is a list of objects to get rid of or dump regularly. Please share with your neighbors.

1. Gutters

This is at the top of the list because almost all houses have gutters and almost all homeowners hate to clean them out. Check for blocked gutters weekly if you have a lot of trees nearby. If gutter status is hard to see, buy a drone to facilitate inspections. If you can’t afford a drone just get an extra-long, telescoping selfie stick for your smartphone.

2. Flexible downspout extenders

Flexible downspout extenders are perfect for mosquito larvae — the ridges hold water and trap organic matter, the black absorbs heat from sunlight (thus speeding development), and female mosquitoes of several species just adore ovipositing inside plastic objects. They are especially bad if nestled in shrubs and ground cover. Note that they hold water even if they are sloped downward. Get rid of them. All of them.

3. Tarps

If you leave a tarp in your yard, you’ve created lots of nooks in which water and debris will accumulate. I frequently see tarps covering soggy logs that owners seem to have no real intention of ever splitting into firewood. I think people view tarps as cloaks of invisibility, magically hiding loathsome to-do items from spouse.

4. Toys

Sandbox toys, sleds, wagons, and kiddie pools seem as if they were specifically designed to encourage mosquitoes. I.e., even when stored upside down they have nooks that collect enough rainwater to allow mosquito larvae to mature. Store them in the garage. If you think covering them with a tarp will work, please see #3.

5. Bird baths

Everyone should have a bird bath. But if you do, you need to either have a water bubbler/agitator (mosquitoes hate that) or you need to kill the larvae by adding granules of Bacillus thuringiensis var israelensis (abbreviated, Bti). Bti is extremely effective: you can add it a container that has thousands wriggling of larvae (see movie) and they will all be dead within hours. Just add it every two weeks and your bath will always be mosquito free. But don’t forget — make yourself a smartphone reminder or write on paper calendar.

Bird bath next to purple coneflowers

6. Trash and recycling bins

If you can’t store your trash and recycling containers under a roofed area, keep a lid on them. I found the ones below behind a local church. Tens of thousands of larvae within.

Recycling bins with stagnant water

7. Watering cans

Watering cans are rarely transparent so you can’t see the mosquito larvae inside, but they are present if you leave them around the yard when it’s been raining a lot. Store them empty, in garage.

8. Wheelbarrows

Just keep them propped up vertically so they don’t accumulate rain water. Or drill holes.

9. Rain barrels

Just put screening over the top. Or add Bti every other week. I don’t recommend adding mosquito-eating fish because they die when water level gets low (plus the fish suffer before dying).

10. Pot saucers

Pot saucers are unneeded outside so it’s easy to eliminate them. If you like them for decorative reasons you’ll need to add Bti regularly. It’s better to just get rid of them because you’ll eventually forget. You know you will.

Other places where mosquitoes larvae thrive

Below are photographs of stagnant water I’ve noticed around my town. On my list of photographs to add: bromeliad, pool cover, bottle cap.

Neighborhood Mosquito Watch

During a run this week I passed an abandoned, 30-gallon aquarium with easily 10,000 larvae doing their thing (wriggling). I came back later, took some photographs (on my Instagram soon if you’re into that), and then dumped it, sending the larvae to their deaths but also releasing a cloud of perhaps 100 newly-eclosed adults. I suspect the aquarium had been there for years, pumping Asian tiger mosquitoes (Aedes albopictus) into the neighborhood. Given the aquarium’s location at the edge of busy parking lot I’m sure that thousands of people have looked at it and thought, “Huh. Looks like an abandoned aquarium full of dirty water. Next to a Christmas tree. I bet there’s a story there!”, and then moved on with their lives.

Abandoned aquarium with mosquitoes

In case you are unsure what an infestation looks like, the next two photographs show what the adults, larvae, and eggs look like. Asian tiger mosquitoes lay eggs singly on the sides of containers or on moist objects floating on the water. They can last over a year as an egg, waiting for conditions to be just right.

Male Asian tiger mosquito (Aedes albopictus) with larvae

Female Asian tiger mosquito (Aedes albopictus) with larvae and eggs

Here’s a sample of the water I pulled from the tank.

But not all the eggs were Aedes albopictus (there are 60 species in PA alone). Here’s a raft of eggs in the aquarium from a different species (Culex sp.). The raft is lodged on a leaf but normally it just floats around until the larvae pop out. Anopheles (another common genus) has eggs that are deposited singly but float with the help of cute little life preservers.

Raft of mosquito eggs

But that’s not all! Yesterday I found a recycling bin behind a church with similar numbers of larvae. Given the amount of leaves decomposing in the bottom I suspect it has been like this for at least the whole summer. Again, it really is strange that nobody did anything about it. It’s right next to a sidewalk that gets lots of traffic (at least on Sundays) and is probably 10′ away from a playground at an infant/toddler daycare center. Poor kids. (I dumped it.)

Recycling bin with stagnant water

Given how much people hate mosquitoes it left me thinking how the public outreach about mosquito control has failed on the most basic level. Everyone should know enough about mosquito biology to know how and where they breed, and everyone should feel empowered to do something. Being proactive is so much better than adopting what I think is the common view, “Well if the mosquitoes get bad enough I’m sure the government will spray insecticides from planes.

All it would take would be a nicely worded message from a town official to mobilize residents into a mosquito watch. Something like, “If you see mosquito larvae swimming around in a container when you are out walking your dog, please turn the container upside down or alert the owner about it. Thanks.”

Pyractomena borealis mouthparts

Here are several anterior close-ups Pyractomena borealis. The telescoping head allows the larva to inject (via curved, hollow mandibles) a numbing agent into snails that have retreated inside their shells. The antennae and maxillae are also partially retractable. When a larva is done feeding on a snail (or slug or earthworm) it will de-slime all of these parts with the hooked, fingerlike projections of the holdfast organ (pygopod) located on the last abdominal segment. The head is also fully retractible (see previous post). These larvae are extremely active, so really hard to photograph.