Still, protection is key.
The easiest, cheapest, least icky, and very effective method: Wear pants and long sleeves. And avoid wooded, grassy areas.
But, of course, there are many chemical repellents.
Products with 20 percent DEET protect against ticks, says the Centers for Disease Control and Prevention. Even so, shower and do a body check after being in a high-risk area.
For mosquitoes, look for products with one of these active ingredients: DEET, picaridin, oil of lemon eucalyptus, or IR3535.
All are widely available, said David Andrews, senior scientist at the Environmental Working Group (EWG) and lead author of a recent report on repellents.
At 21 pages, it may be more than you want to know, but it's based on the latest peer-reviewed literature (at www.ewg.org).
If time is short, here are two take-away points:
1. The four commonly used chemicals are all effective and, in lower concentrations, safe. This is saying something, given that the EWG is skeptical about chemicals. But as the report notes, given the potential for West Nile and Lyme, "which is worse, bug bites or bug repellent?"
The EWG even listed DEET as its top pick, noting that it is quite effective and that its safety profile is "better than many people assume."
2. A higher concentration doesn't work better, just longer.
"If you're only going to be outside an hour or two, 10 percent products are enough," Andrews said.
The report recommends nothing stronger than 30 percent DEET.
The EWG dismisses zappers and citronella candles as ineffective. Likewise, the researchers are leery about clip-on devices that emit repellent into the air. The chemicals are more toxic than those in skin-applied products; you may not want to be inhaling them.
Don't use products that combine repellent with sunscreen. If you need both, first apply the sunscreen, which has ingredients to help it penetrate the skin. You want the bug repellent to stay on top of your skin.
Aerosols can be inhaled. Use lotions, pump sprays, or towelettes.
Wash the repellent off when you come inside.
The rules change for infants and young children. Don't apply oil of lemon eucalyptus on children younger than 3 years. The EWG further recommends no repellents on children younger than 6 months. Instead, use fine netting over strollers.
Don't put repellent on children's hands, which often go right into their mouths.
If you're still not enthusiastic about chemicals, there's always the method that Frank Swift swears by - and that many groups also suggest.
He's president of Swift Food Equipment Inc., in Philadelphia, and one restaurant appliance he sells is a "wind curtain." It keeps out insects because they can't fly against a strong breeze.
He found he could create pretty much the same thing at home. "I did field research, which means I put a fan next to me," Swift said. "It works."
"GreenSpace," about health and the environment, appears every other week. Contact Sandy Bauers at 215-854- 5147, sbauers@phillynews. com, or on Twitter @sbauers. Her blog is at www.philly.com/greenspace.