Keeping the mosquito threat in check

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Mike will appear at the Fredericksburg Spring Home Show on Saturday and Sunday, March 18—19, at the Fredericksburg Expo Center in Fredericksburg, Virginia. Mike will speak at noon and 3 p.m. on March 18 and at noon and 2 p.m. on March 19. Find out more on the show’s website.

It’s time to talk mosquito prevention

There’s still the “new” Zika virus to fear, and we’ll also see the return of old favorites like West Nile with the arrival of the warmer weather we’re otherwise looking forward to. But you can greatly diminish the number of mosquitoes that would otherwise plague your backyard this summer by taking action now.

If you knock down the numbers of the first couple of generations, you’ll get the math on your side for a change — they’ll still grow exponentially, but if that first number is two as opposed to two thousand, you’re on your way to a bite-free summer.

Step one: clean up any trash in your yard; mosquitoes can breed in bottle caps, plastic bags and other places you might not expect.

Emptying standing water is no longer enough

Rutgers entomologist Dr. Dina Fonseca recently explained to me that this is the perfect time to begin limiting, or perhaps even preventing, mosquito problems near your home by interrupting their breeding cycle.

But to do that, she explains, you need to know that there are two types of mosquitoes in our region, and the more recent arrival, the day-flying Asian “tiger mosquito” (Aedes) has a very different life cycle than the “old friends” we’re used to.

These biters spend the winter in the egg stage, but those eggs aren’t floating on the surface of standing water — they’re attached to the sides of the water-holding objects, ready to be activated when the weather warms and the water level rises after a rainfall.

As such, just dumping out wheelbarrows, recycling bins, children’s toys and the like isn’t enough with these terrors. You also have to scrub the eggs off any items that can hold water to destroy them. And then, of course, make sure those containers stay dry.

Getting rid of old-school water breeders

The “Culex” mosquitoes we all grew up with — the ones that mostly bite when day changes over into evening — are already among us. The last females of summer hibernate in sheds, garages and other protected areas, emerge on the first nice day looking for a blood meal and then seek out standing water in which to lay their eggs.

The old advice was to dump any water on your property to deny the mosquitoes that breeding ground. And that’s still excellent advice. But now there’s a new twist on that advice that uses water against them.

BTI, the active ingredient in mosquito dunks and granules, prevents those eggs from becoming biting adults. So if you deliberately put out standing water laced with BTI, the females will lay their eggs in the water, but no new mosquitoes will be born. And BTI — a naturally occurring soil-dwelling organism — is nontoxic to other creatures. It has no effect on fish, birds, pets, people, toads, etc.

The biggest brand name you’ll find at retail stores is Summit. They offer a wide array of formulations. And the mail-order firm Gardens Alive sells BTI in granular form as “No-Squito” — which, they tell me, is supposed to rhyme with “mosquito.”

Don’t be foiled by flowers

The Rutgers entomologist also told me something that I had not previously known about mosquito behavior.

Early in the spring, biting females — who we tend to think of only as blood suckers — also feed on the nectar of small-flowered plants for energy. But those are the exact same kinds of plants skilled gardeners use to lure pollinators and beneficial insects to their backyards!

The answer? Once again, BTI traps.

Place small containers of water near your earliest-blooming flowers, treat the water with BTI, and the females who visit the flowers will lay their eggs in this convenient water source, but no adult mosquitoes will emerge!

And don’t forget the gutters

To review:

  • Empty and scrub plant saucers, outdoor children’s toys, recycling bins — anything that can hold water.
  • Don’t let those containers fill up with water again. Unless you treat the water with BTI.
  • Clean up any small trash in the yard. One of Dr. Fonseca’s colleagues has shown that the Aedes mosquito (the day-flying Asian Tiger kind) can go from egg to adult using the amount of water in a bottle cap.
  • Put containers of water laced with BTI around your home and freshen up the BTI as directed.
  • Make sure some of those traps are near early-blooming flowers.
  • And if you have gutters, clean them out as well. They don’t even have to be clogged to be dangerous — just a low spot that doesn’t drain well can breed these ancient disease-carrying enemies of mankind.


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