Stop mosquitoes from becoming biting adults

Your landscape and local area may not have been affected by the flooding, but there has been a lot of rain in many parts of the country. Even without flooding, summer is when mosquitoes reign.

Mosquito-borne diseases killed many settlers and their livestock before wetlands were drained and insecticides were widely used. Even though mosquitoes are not nearly the problem they once were, they still transmit diseases such as West Nile virus that moved from Africa to the United States. Mosquitoes also transmit several varieties of encephalitis and the nematode that causes dog heartworms. If you are a gardener or just want to relax outdoors, preventing mosquitoes from becoming biting adults is key to reducing the population.

There are about 200 species of mosquitoes in North America. Mosquitoes can be grouped by how and where they lay their eggs. Floodwater mosquitoes lay their eggs on low-lying dry ground that is later flooded. High water levels may cause enough flooding that eggs that were laid over the previous two or more years may hatch all at once.

Under summer temperatures, the adults will emerge about two weeks after the initial rains or flooding and then they can be a nuisance for about two weeks. Some of these mosquitoes will fly more than 10 miles from flooded areas, and maybe farther with strong winds.

Container-breeding mosquitoes lay their eggs in anything that will hold water. Eggs are laid on or near the water surface and hatch within a few days. A couple hundred of them together look like a quarter-inch speck of dust floating on the water. The larvae become “wigglers” that squirm their way down into the water when disturbed. Container mosquito adults live a week or two.

All male mosquitoes drink nectar from flowers and do not bother people. The females must drink some blood before they can produce any eggs. Some species prefer mammals and some prefer birds, but they will take what comes their way. Most species prefer feeding in low light levels at night, late evening, early morning or in the shade.

Treating for the larval stage is the most effective way to control mosquitoes. Adult insecticide sprays may seem potent, but they are not as effective at controlling mosquitoes.

Controlling container mosquitoes begins with making sure they do not hatch. Do you or any of your neighbors have any of the following potential mosquito nurseries?: Old tires, buckets, swimming pool (even a tiny one), rain gutter, rain barrel, flat roof, leaking faucet, air conditioner unit puddle, bird bath, fountain, pond with no fish, puddles, tree holes, low area flooded by sump pump water or septic tank, animal water bowls, irrigation water that puddles, flower pots with saucers or any other thing left out that collects water. Drain every one of these locations at least weekly. Any puddle that lasts more than four days could produce mosquitoes.

In locations that cannot be drained, the best step is to kill them during the larval stage. A safe, nontoxic way to control mosquitoes is to use a product containing a biological larvicide called Bacillus thuringiensis subspecies israelensis. There are several brands that use BTI, and some of them have a slow release method of dispersal.

Mosquito Dunks from Summit have been around the longest and I have found they work very well. They look like small compressed sawdust donuts that float on water in containers. The bacteria kill mosquito larvae before they become flying, biting, disease-spreading adults. A dunk can be tied to a tree trunk in areas that flood, so each time water comes, causing mosquito eggs to start growing, it also starts releasing the bacteria from the dunk.

The bacteria are ingested by the larvae as they feed and the larvae then get sick and die. The bacteria do not affect fish, mammals, birds or bees. Some other varieties of B.T. do affect caterpillars of moths and butterflies.

Mosquito Bits from Summit can be sprinkled into any container to kill mosquito larva in less than 24 hours. I use them in water garden containers and rain barrels that I don’t want to see a dunk floating around.