Are You Growing a Crop of Mosquitoes in Your Backyard?

Wherever you live, in the desert or a mountain meadow, mosquitoes also live. California alone has more than 50 species. Now that West Nile Virus has made its preview in our state, more people are realizing that mosquitoes are more than a nuisance. They're a health threat. And they've long been a threat to our pets.
Fortunately for those of us in the Shasta County area, the outlook for the mosquito population this year is pretty good. According to John Albright of the Shasta Mosquito and Vector Control District (SMVCD) the combination of winds and high temperatures in recent months should result in conditions that will help hold down mosquito breeding.

The SMVCD places traps in 20 locations around the area so they can predict with some accuracy what we can expect in terms of the mosquito population. So far, it's looking pretty good, says Albright, but he warns this could change. Rain or other conditions that result in standing water could cause population growth. To a mosquito mama, standing water is the ideal nursery she's looking for to hatch her young. Give her a mere half-inch of still or stagnant water and in less than a week she's created new life that longs for your blood and your pets' blood.

Get rid of the standing water at least once a week and you've taken a key step towards protection for your family. The trouble is, it is easy to overlook places where water might build up. Here is a list of places to check, and some ideas for protecting your pets from mosquito-borne diseases.

Threats to Pets

Animals. Your dogs and cats are not at great risk for West Nile Virus. They can be infected, but rarely become ill and do not spread the virus. But many species of birds are susceptible to mosquito bites and can die or become ill. You can protect indoor birds by making sure your screens are secure enough to keep bugs out. And protect outdoor cages with mosquito netting. West Nile virus however is deadly for horses, though a vaccine is available.

Dogs and cats that are bitten by mosquitoes are at risk of developing deadly heartworm. Mosquitoes that bite infected animals carry the disease to their next bite victim, causing pets to become seriously ill. Staff at the Anderson Veterinary Clinic report that deadly heartworm is prevalent in Shasta County, so it is critical that pets are treated with heartworm prevention monthly

Where to Check for Mosquito Nurseries

Chain link fences with open posts. You can prevent water from filling the posts by adding caps.

Patio furniture and garden ornaments. Check to see that their nooks and crannies have not collected water.

Low-lying areas. When you irrigate, look to see if water collects there.

Plastic mulch. Replace it with landscaping fabric that prevents weeds while still allowing water to pass through.

Faucets, hoses, and air conditioners. Are they leaking and allowing water to build-up?

Garden lights. Ensure that water is not building up inside or in the caps.

Boats, canoes, and cargo trailers. Look them over to see if they have standing water in them.

Containers like boxes, buckets, cans, cups, jars, and pots to see if they are holding water. Cover them or turn them upside down to prevent build up.

Pet water dishes. Change the water at least once a week, but daily is better. Pets like fresh water too.

Play equipment like slides and swing sets. If they have poles that can collect water, drill holes.

Tire swings (or just old tires). Tires are the most common breeding ground for mosquitoes in the United States. Dispose of old tires properly. Or, if you use them for retaining walls, landscaping, or swing sets, drill holes in them to allow adequate drainage.

Birdbaths. Clean or hose them out once a week.

Ponds. If you have a water garden, aerate the water. Or you can add mosquito fish or use mosquito dunks (more about these later).

Outdoor drains. Check to see if they have become blocked.

Wading pools and wheelbarrows. Store vertically or upside down.

Pools and spas. Whether they are in use or not, you need to treat them with chlorine to avoid spawning mosquitoes.

Pools covers. Is there standing water on top of the cover?

Rain gutters. These are often forgotten areas but mosquitoes love them.

Recycling bins. Make sure they have drainage holes in the bottom, not just the sides. If items sit in the bins for more than a few days, turn anything that can hold water upside down, like jars and bottles.

Screens. Make sure they fit well and are tight enough to keep mosquitoes out.

Shrubbery. Keep shrubs trimmed and thinned during hot weather. Mosquitoes like to hide in them during the hottest times of the day

Potted plants. Don't over water. Drain saucers often.

Tree stumps and hollow trees. If the trees have hollows where water can collect, fill them with sand or mortar.

Umbrella stands. If the base is filled with water, cap it tightly and seal it with duct tape, or drain the water and fill the stand with sand.

Basketball hoop. Check the base for standing water and draining.

What Can You Do if You Have a Mosquito Problem?

Dunks. Dunks are doughnut-shaped blocks that contain a pesticide called BTI. BTI kills mosquito larvae but is non-toxic to animals and fish when used properly. Dunks dissolve in water, and are available at hardware and garden stores.

Mosquito Fish. These are tiny fish that eat newly hatched mosquito larvae. For people who choose to have standing water in such things as unused swimming pools, ornamental pools, ditches, sumps, and water troughs, contact your local vector control agency to inquire about mosquito fish. The SMVCD will provide these at no charge, as will many other vector control agencies around California and elsewhere.

Traps. Tests show traps using carbon dioxide are effective at reducing mosquitoes in the immediate area. But university tests show that ultrasonic repellers that emit high-frequency sounds (bug zappers) do not reduce mosquito numbers. In fact, Albright says that he has seen "not one shred of evidence" that these devices work against mosquitoes, other than the claims made on the packaging and advertising.

FOR MORE INFORMATION, contact your local mosquito control district listed in the government section near the front of your phone book (in Anderson, the number is 530-365-3768) or on the Web at www.mvcac.org/agencies.htm.