On Sunday evening, four planes covered the remaining 226,000 acres to complete the first round of application in those areas of Dallas County participating in aerial spraying. Weather permitting, five planes will apply a second round of insecticide tonight to the entire target area of 362,328 acres.

Spraying will begin at 9 p.m. today in the city of Dallas, earlier in other participating cities. Residents in all neighborhoods of Dallas should expect spraying to occur sometime between 9 p.m. and 1 a.m.

Since the insecticide Duet only kills adult mosquitoes, the second round of spraying is intended to kill larvae that have hatched since the first spraying.

Representatives from the Centers for Disease Control will be in North Texas this week, surveying and analyzing the region’s efforts to combat the West Nile Virus and will make recommendations on how to proceed.

“Now that the aerial assault is showing positive preliminary results, we need to expand our assault on the ground and enlist residents to join the fight by draining standing water to cut off mosquito breeding grounds,” Dallas Mayor Mike Rawlings said in a release. “It only takes a little soil, compost or a few leaves, and water that stands stagnant for 1-2 weeks, to breed mosquitoes.”

To help eliminate mosquito breeding grounds, Dallas residents are encouraged to take the following steps:

• Empty or get rid of cans, buckets, bottles, old tires, empty pots, plant saucers and other containers that hold water.

• Keep gutters clear of debris and standing water. Remove standing water around structures and from flat roofs.

• Change water in pet dishes at least once a day. Change water in wading pools and bird baths several times a week.

• Fill in low areas in the yard and holes in trees that catch water.

• Maintain your backyard pool or hot tub and be sure someone takes care of it if you are out of town.

• Stock ornamental ponds with fish that eat mosquitoes.

• Cover trash containers so they will not collect water.

• Water lawns and gardens carefully so water does not stand for several days.

• Repair any leaking plumbing and outside faucets.

• Screen rain barrels and openings to water tanks or cisterns.

• Keep drains and ditches clear of weeds and trash so water will not collect.

Residents are advised to take the following precautions:

• Avoid being outside during spraying; close windows and keep pets inside.

• If skin or clothes are exposed, wash them with soap and water.

• Rinse homegrown fruits and vegetables with water as a general precautionary measure.

• Cover small ornamental fish ponds.

• Because the chemical breaks down quickly in sunlight and water, no special precautions are suggested for outdoor swimming areas.

Our suggestions during spraying:

• Keep pets in — don’t just “consider” it.
• Wash any homegrown fruit and vegetables thoroughly, don’t just rinse.
• Cover fish ponds as well as swimming pools, if you have a cover.
• Before using a swimming pool again after spraying, add one or two extra chlorine tablets and run the filter several hours.

Here’s why:

The chemicals used in Duet, phenothrin and pralletrin, are serious poisons.

In one study, phenothrin is linked to breast cancer. In cats, the chemical was used in flea collars but was banned after it was found to cause hair loss, salivation, tremors and numerous deaths in cats and kittens.

Pralletrim is associated with irritation of skin and eyes, headache, dizziness, nausea, vomiting, diarrhea, excessive salivation, fatigue. In more severe cases, the chemical can cause fluid in the lungs and muscle twitching may develop.