(ABC 6 News) – A bug bite can leave more than just an itchy bump.

Mosquitoes can spread diseases like the West Nile virus, and ticks can transmit many diseases, including Lyme and Rocky Mountain spotted fever.

As Consumer Reports explains, the best offense is a good defense, which includes using insect repellent that keeps pests away.

Every year, Consumer Reports tests lotions, sprays, and wipes, including plant-based repellents on real people using real mosquitoes to find the best insect repellents.

A repellent fails if a mosquito bites twice in one 5-minute session. Or if there’s one bite in each of two consecutive 5-minute sessions.

“We currently test repellents against only mosquitoes, but in past years, we’ve found that repellents that worked well against mosquitoes also tended to work well against ticks,” says Consumer Reports’ Catherine Roberts.

The results: the most effective repellents against mosquitoes and ticks contain 25-30% Deet as the active ingredient.

At the top of CR’s ratings are: Ben’s Tick & Insect Repellent Wipes, Ben’s Tick & Insect Repellent Wilderness Formula Pump, and 3M Ultrathon Insect Repellent8. All excel in protection.

If you’re concerned about using Deet, Roberts says, “Our ratings include over 50 repellents and more than 20 recommended ones, so it should be easy to find a way to beat the bugs that’s right for you.”

CR found products with 30% oil of lemon eucalyptus as good alternatives, like Repel Lemon Eucalyptus Insect Repellent Pump. CR’s ratings also have a few high scorers that contain 20% picaridin, like Sawyer Premium Insect Repellent Pump.

Correctly applying the repellent is just as important as the kind you use. Follow the directions on the label, and use a thin coat on all exposed skin.

You can also spray on top of your clothes, but don’t apply under your clothing.