A few preventions tips during West Nile outbreak
Over the past few weeks, it has been difficult to ignore the West Nile Virus outbreak. Almost daily another report of more confirmed cases and possibly deaths occurring from the disease. To help you make informed decisions regarding protection, treatment, and control, here is a report and some information from a fact sheet complied by Dr. Mike Merchant, extension entomologist in the trenches of DFW.
His information should help everyone to protect themselves from the threat of WNV, as well as offer some ways that we each can help combat its spread in our area.
“Rains have not been abundant this summer in North Texas, but an early jumpstart from the mild winter has given mosquitoes all they need for a mid- summer resurgence, said a Texas AgriLife Extension Service entomologist.
“ Mosqui toes and mosqui - to-borne disease are a major problem in the Dallas Fort Worth metroplex this summer,” said Dr. Mike Merchant, AgriLife Extension urban entomologist at Dallas. “This is one of the worst years we’ve seen in north Texas for the mosquito-borne disease called West Nile virus, and the season is far from over.”
Merchant advises Texans to be aggressive in dealing with the blood-sucking critters. As a first line of defense when going outdoors, especially at dusk or early morning, everyone should use insect repellent, preferably one containing DEET, IR-3535, picaridin or lemon oil of eucalyptus, as recommended by the Centers for Disease Control.
But that’s not all. There are some practical steps everyone can take to further reduce mosquito risk around the home, he said.
“The first step is to make sure mosquitoes aren’t breeding on your own property,” he said. “It only takes a little water standing for a week or so to breed mosquitoes. And even without rain, stagnant water can come from shrinking ponds or creeks, irrigation water, or even washing the car.
“Some of the most common places to find standing water this time of year are in water catch basins, storm drains, flower pot dishes, untended water features and neglected swimming pools. After a summer shower, make sure you don’t have small containers, wheelbarrows or even children’s toys holding water.”
Merchant said standing water in catchment basins, ditches and other hard-to-drain sites can be treated with an insect growth regulator containing methoprene or the bacterial insecticide Bti. These insecticides are safe for the environment and come in dissolvable doughnut, briquettes or granular form.
“ We usually don’t worry much about fish ponds, streams or creeks, because fish usually take care of the problem there,” he said. Once possible breeding sites are eliminated, Merchant said there are several options for eliminating mosquitoes that still find their way into the yard.
“Knowing how mosquitoes behave and using the right products can make your home safer, inside and out,” he said.
He said mosquitoes spend most of their time during the day in shady resting sites around the backyard. Treating sites like tall grass, shrubs and trees, as well as shaded eaves, walls and especially doorways of the house can provide significant mosquito suppression.
“When you treat shaded doorways you can eliminate those mosquitoes that often get swept into the house when people come and go. These are some of the worst offenders because people don’t generally wear repellents indoors,” Merchant said.
Pump-up and hose-end sprayers and aerosol cans for backyard use can also be used to treat trees, shrubs and ground cover where mosquitoes rest during the heat of the day. Merchant said to look for products that promise multi-week control. Insecticides containing lambda cyhalothrin, deltamethrin and cyfluthrin are good choices when the goal is long-term mosquito control.
“I’m not usually a fan of using broadcast pesticide applications in the backyard, but mosquitoes are serious business, especially this year,” he said.
If you don’t like the idea of treating yourself, and mosquitoes are a problem, another option is to hire a pest management company. Professionals have the tools and knowledge to apply insecticides properly and to successfully control mosquitoes.
If you choose to do it yourself, Merchant advises reading and following the pesticide label directions carefully. “If you wear the recommended gear, and apply when and where the label says, you can do your own mosquito control safely. All landscape sprays should be applied in the evening or early morning before bees and but ter flies are active. Don’t spray insecticides on windy days or when rain is expected.
Additionally, if you have areas that cannot be drained of water, you can treat with Bt dunks or Altosid granules. These are safe for use in water troughs.
Some quick facts about mosquito life cycle, breeding, and water sources:
• Once mosquitoes find a suitably polluted puddle of water, they lay eggs. Eggs take about a day to hatch and the larvae 5-8 days at 30 degrees C (86 deg F). Once they pupate it’s another 36 hours before the adult emerges. So it takes 10-14 days typically for development. Standing water must remain for about that length of time before it is likely to breed mosquitoes.
• Clean water is not so much an issue, but if rain water is mixed with leaves and/or soil and sits in the sun for a week or so, it gets pretty attractive for mosquitoes. In addition, water where fish are present, such as a pond or permanent stream is not usually a big source of mosquitoes.
Remember the 4 D’s
• DUSK/DAWN—Stay indoors at Dusk/Dawn. This is the time of day that mosquitoes are most active.
• DEET—Use insect repellents that contain Deet when going outside, especially at times closer to dawn or dusk when mosquitoes are most active.
• DRAIN—Remove all areas of standing water. Examples are pet dishes, birdbaths, and water dishes under potted plants. Repair faulty French drains. Remove debris from rain gutters. Mosquitoes will breed in this debris since it is normally damp under the debris. Remove all piles of dead leaf material from under trees and shrubs. This also is a breeding site.
• DRESS—Avoid being bitten by mosquitoes by wearing light colored long sleeved shirts and long pants when going outside.