To fight off mosquitoes and ticks—and avoid the diseases they can spread—you need an effective insect repellent. But even the best bug spray won't help much if you don't apply it properly. And though repellents are generally safe, even for pregnant women and children, that's only true if you put them on correctly.

"A quick, absent-minded spray won't provide enough protection," says Ed Kippel, who led insect repellent testing here at Consumer Reports for more than two decades. "But too much, or applying bug spray in the wrong way, may pose risks, especially for young children," he says.

You should always follow instructions on the product label, Kippel says. But that's not the only thing to keep in mind. We spoke with experts at the Centers for Disease Control and Prevention, for their best advice on how to safely and effectively apply bug spray.

1. Apply Sunscreen First

If you’re going to be in the sun, first rub in your sunscreen, let it absorb into your skin, then apply the repellent on top.

If you need to apply more sunscreen later, you don’t necessarily need to reapply bug spray, Kippel says, unless you notice that the insects are beginning to bother you.

Note that we don't recommend products that combine a sunscreen and a repellent—and neither does the CDC. That's because sunscreen should be reapplied more often than bug spray, so you could end up applying more repellent than necessary.  

2. Put It on Smoothly and Evenly—but Not Too Much

Mosquitoes and ticks can be aggressive biters, especially the Aedes aegypti mosquitoes, which are primarily responsible for spreading Zika. They can find and bite an exposed section of skin the size of a dime. So you want to make sure you cover every inch.

Shake the bottle and spray evenly onto your uncovered skin and clothes from about 4 to 8 inches away, as directed on the label. But don't overdo it: For insect repellents, more is not better. You don’t want to lather insect repellent on like a thick lotion. Rather, a light dusting is sufficient.

And it’s best to avoid breathing in repellent, so try to be in a well-ventilated space away from open flames when applying.  

3. Don't Spray Under Your Clothes

Though wearing long-sleeved shirts and long pants can help you avoid mosquito bites, you should still spray your clothes with repellent for extra protection. (First apply to an inconspicuous location to check for possible damage.)

But never spray it underneath your clothes: That's not only unnecessary but also may increase the risks. (Interested in insect-repellent clothing? Read our report on shirts treated with permethrin.)  

4. Use Your Hands for Sensitive, Hard-to-Reach Spots

Never spray repellent directly onto your face or your ears. Instead, spray some onto your hands and spread it on your face, neck, and outside of your ears, being careful to avoid your eyes and nostrils. Don’t forget to rub it onto your head if you’re bald.

Bug sprays can aggravate open cuts and wounds, so avoid areas with broken or irritated skin.

And if you’re going to be eating, wash your hands after applying. 

5. Don't Forget Ankles and Knees

Mosquitoes tend to be attracted to certain hot spots on the body, including the ankles, feet, and knees. And because ticks usually hop onto you from plants on the ground, your exposed ankles are a primary target.  

6. Take Extra Care With Kids

According to the CDC, you should never apply any kind of insect repellent to children under the age of 2 months. For older children, never spray directly onto their skin.

Spray onto your hands first, then rub onto their exposed skin and face. Be sure to avoid their hands, because they tend to stick their fingers into their eyes and mouth. And as always, avoid their eyes, nostrils, and mouth when rubbing.

7. Reapply Only When Necessary

Our top-rated repellents all protected against both ticks and mosquitoes for at least 7 hours in our tests. Still, some people tend to attract more bugs than others, according to the Environmental Protection Agency, so if bugs are starting to bite again, that’s your cue that it’s time for more.

Insect repellents can also wash off in water, so if you’re swimming or perspiring heavily, you should think about reapplying afterward.