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Diggin' In: As fall arrives, give mosquitoes the cold shoulder

September 29, 2014

September is iffy when it comes to mosquitoes. The month can be good or it can be bad, depending on weather patterns.

Generally speaking, July and August tend to be somewhat drier months in most states nationwide, which helps keep mosquito numbers down, according to experts.

Come September and early October, rainfall makes the difference.

"When the season starts changing, we tend to get more rain," says Leah Aguilar, operations superintendent with mosquito control in coastal York County, Va.

"This combined with still-warm temperatures can produce large amounts of mosquitoes. Of course, the flip side of that is true too; if in September we are dry, then mosquito numbers will stay low."

Most coastal areas are home to a dozen or more different types of these pesky biters. Worldwide, there are 3,000 different species of mosquitoes with 176 recognized in the United States, according to the American Mosquito Control Association, www.mosquito.org .

But, the Asian tiger, or Aedes albopictus, is the real concern, according to Aguilar.

"This mosquito breeds in containers of still water and is a daytime biter," she says.

"This makes it especially hard to control because we spray no adulticides during daylight hours; this mosquito is best controlled in the larval stage. This is where education is critical; we are trying to focus on educating the public about eliminating standing water in their yards and neighborhoods."

Currently, York County promotes mosquito-repellent gardening, targeting small areas such as patios, and encouraging people to add plants that are shown to repel mosquitoes, according to Aguilar.

One plant cited at www.yorkcounty.gov/mosquitocontrol is horsemint, a perennial that gives off a strong incense-like odor that confuses mosquitoes by masking the smell of its typical hosts. Its flowers also benefit bees and butterflies. Other plants that deter mosquitoes include lavender, basil, rosemary, thyme, lemongrass, mums, ageratum, catnip, pennyroyal, marigolds, garlic, citronella, feverfew and pineapple weed.

This winter county mosquito-control people will make some sample mosquito repellents from the suggested plant, hoping to teach interested residents how to do the same.

"Additionally, we are studying Native American ethnobotany to see how plants were used historically and how we may be able to incorporate that into our efforts today," she says.

"And, we are participating in a study right now that is testing garlic bait for mosquito abatement. Treatments like this are currently being used overseas but not really in this country."

Here’s how to enjoy a mosquito-free good life outdoors, according to York County experts:

*Ensure that drainage ways and ditches in and around your yard are clear of obstructions and draining. Grass in ditches should be regularly mowed and maintained. Do not kill all vegetation in ditches with herbicide; this will only create erosion and more problems for mosquitoes and your yard.

*Do not dump grass clippings or yard debris in and around your yard or in drainage areas. Piles of grass clippings are favorite hiding places for mosquitoes.

*Eliminate all standing water sources around your home:

Turn over buckets, wheelbarrows, toys, etc. to prevent standing water.

Change bird bath and non-filtered pool water weekly or treat with biological control, such as Bti larvacide.

Clear gutters regularly; obstructed gutters are a prime breeding location.

Shake out any tarps weekly.

Remove any old tires and dispose of them properly.

Cover and treat rain barrels with biological control such as Bti larvacide.

*Add mosquito larvae eating fish (Gambusia holbrooki) to ornamental ponds or depressions with permanent standing water.

* If you have tubing connected to your rain gutter down spouts, ensure that the tubing is facing down so that water can flow out of it. These tubes, especially black ones, hold small amounts of water and are especially attractive to mosquitoes.

*Dispose of all old tires in and around your yard or drill holes in them to make sure they do not hold water.

* Incorporate mosquito repellent plants into your landscaping and place mosquito repellent plants in pots around entrances or decks. Mosquito repellent gardening is most effective in small areas. . You could also add species that attract mosquito predators, such as dragon flies.

*Make your own mosquito repellent by combining essential oils from mosquito repellent plants, such as citronella, lavender, or lemon balm with a base such as witch hazel or olive oil.

At the end of the season, cut and dry your annual insect repellent plants. These cuttings can them be crumbled up and used as potpourri around your living areas inside and out.

Use citronella candles around your yard and porches/decks. Citronella oil comes from plants, which can also be planted in your yard.

Sweet basil has been shown to repel both flies and mosquitoes; add pots of basil near entrances to your home.

When you grill outdoors, with charcoal, once you are finished cooking, add a bunch of sage or rosemary directly onto the coals. The smoke in combination with the plants repels mosquitoes.

Prune bushes, shrubs, trees, and ivy in your yard. These plants offer hiding places for mosquitoes. Trim back any vegetation that is touching your home.

Use Bti larvacide "donuts" for permanent standing water sources, such as ground depressions or rain barrels. Bti (Bacillus thuringiensis israelensis) is a naturally occurring bacterium that is deadly to mosquito larvae but harmless to other living things, according to the makers of Mosquito Dunks, which contain Bti as the active ingredient. Bti keeps mosquito populations down, — female mosquitoes lay eggs in standing water treated with Bti — and mosquito larvae hatch, eat the Bti spores and die before maturing into biting adults. Bti does not adversely impact other insects, including bees and butterflies, nor does it harm animals, fish, birds, people or plants, according to experts.

 

 


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