Category Archives: Biology

Eliminate mosquitoes by eliminating stagnant water

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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 the black absorbs heat from sunlight (thus speeding development). 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

Other objects of concern are: pool covers, pot saucers, grill covers, plastic kid toys, tires, unattached hoses, empty glazed pots, shovels, construction materials, garbage cans, garbage can lids, containers in recycling bins, bottle caps, cemetery vases, decorative shells, empty coconuts, papaya tree stumps, downspout troughs, spigot drips, ollas, pickup truck beds, window wells, septic tanks, uncapped metal fence posts, animal tracks. Mosquitoes will also lay eggs inside in toilet bowls, animal water dishes, and French drains.

  • Recycling bin lid
  • Buckets at community garden
  • Plastic bag with stagnant water
    Garbage bags
  • Water sprinkler with stagnant water
    Upside-down sprinklers
  • Pool floats
  • Plastic mulch sheets
  • Driveway potholes
  • Fire pit with stagnant water
    Fire pits
  • Bamboo garden stakes
    Bamboo garden stakes
  • Bamboo culm stumps
  • Tree holes
  • Sump pump outflow with stagnant water
    Sump pump outflows
  • Uncovered dumpster with stagnant water
    Uncovered dumpsters
  • Uncapped, hollow traffic barriers filled with stagnant water
    Uncapped traffic barriers
  • Basketball hoop ballasts

How to protect yourself from ticks

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I spend a lot of time outside, sometimes face-down in the weeds trying to get a photograph of something small. So I have some opinions about tick prevention and thought I’d share.

blacklegged (deer) tick on sock
Ixodes scapularis
  1. Spray or soak shoes, socks, pants, shirts, hairband, hat, etc., with permethrin (buy online or at outdoor stores), then let dry before you using. Chemical only slowly washes out so you only need to reapply every 5th laundering or so (or after 5 months if you don’t wash your clothes). Spray your backpack with permethrin, too, because you likely set that on the ground during breaks. Do not spray permethrin on your skin. You can also buy clothing that comes pretreated with permethrin.
  2. Spray your clothes and skin with DEET, picaridin, para-menthane-3,8-diol, IR3535, or 2-undecanone. DEET really is the best. Note that “pure” oil of lemon eucalyptus (extracted from Corymbia citriodora) is not currently recommended by the CDC; the oil has small, variable levels of para-menthane-3,8-diol but apparently not enough. All of these repellents do not last like permethrin so reapply every few hours. Do not spray DEET on anything plastic (it will melt).
  3. Be suspicious of “natural” or “organic” concoctions that claim to effectively deter ticks. If one of these recipes actually works the CDC would recommend it. I’ll update this page when that happens. Similarly, avoid apps, crystals, and dietary supplements. If you need help convincing a friend to just use DEET (it’s super safe), mention that DDT is a different chemical that just happens to start with the same letter. DEET is also gluten and GMO free.
  4. Wear light-colored clothing so you can better see ticks. Like this person. Note that this strategy fails with tick larvae because they just too small to see unless you are wearing something pure white and have really good vision.
  5. Tuck your pants into your socks. Like Kanye West. You can even buy tick socks that are treated with permethrin and have a tight weave that prevents larvae from burrowing through the fabric.
  6. Wear tall, light-colored, glossy boots that ticks can’t easily climb. I suspect that larvae and nymphs can still climb glossy surfaces, though. I own a pair of Muck Boots and they have a neoprene surface that I suspect ticks can easily scale. I’m considering switching to something like a Gumleaf boot.
  7. Buy some gaiters and treat them with permethrin. Some gaiters are even designed to keep out ticks. Some even come in lime green. (NB: Lyme disease is named after Lyme, CT.)
  8. Buy some arm sleeves. Like gaiters, you can even buy ones that are already infused with permethrin.
  9. Shave your legs.
  10. Keep checking for ticks as you hike. If you are hiking with others, scan them for ticks, too.
  11. Keep a roll of duct tape handy so that you can easily remove ticks. Travel-sized lint rollers are good, too, and easily attach with a carabiner to a backpack.
  12. Put your field clothes into quarantine when you come home. Ideally, launder them immediately. Ticks can wander off of clothing and backpacks and show up later.
  13. Get naked and check for ticks. Everywhere. This is a really good reason to get a girlfriend or boyfriend even if you’re not really into them. Don’t tell them that.
  14. If you have limited neck mobility, invest in a nice automotive inspection mirror so you can see all the various parts of your body you never look at. You can even buy lighted ones. You can also use a selfie stick and a smart phone, but that’s risky if you accidentally forget to delete the photographs and video.
  15. You probably don’t want to know this but ticks are fond of lodging in ears. Get yourself an otoscope if you feel something in there. You can even buy phone attachments to get pics.
  16. If you find a tick that is attached, take a photograph (like this) then remove the tick. Carefully. I have a Tick Key (see one in action) but there are lots of types. Then take photographs of the bite location and of the tick. If you live in Pennsylvania, send the tick out for free testing. If you live elsewhere, put the tick in vodka or in the freezer in case you need to get it tested later.
  17. Take a long hot bath with a lot of soap. Ticks are hardy but you might dislodge an unattached nymph that somehow got past your first-line defenses.
  18. Once you are de-ticked and clean and have the laundry running, post photograph of tick on iNaturalist so you can get an identification. Here are the ticks of North America on iNaturalist. You can also send pics of ticks to TickEncounter for ID.
  19. Monitor the attachment spot closely. If a red spot appears, take daily photographs with ruler in frame so that doctor can assess progress of redness. Here are pics of Lyme rashes. You can even mark the progress with a Sharpie. There are plenty of other diseases transmitted by ticks, though, so don’t rely on rashes.