Um, lacewings are beneficial bugs and shouldn't be killed. Perhaps you mean some other pest.

Are they getting enough water?

Lacebugs are a problem for azaleas, as well as whiteflies. Try hosing them off with a strong jet of water from the hose. get down low so you get under the leaves. Follow up with insceticidal soap. Do it again in a week.

Next year, start earlier with the hosing and get the population knocked down before they explode. Then you shouldn't have to do it as often.

I use to gather pine tree needles and place under the bushes every spring.They were beautiful.

Ah, lacebugs! Yes, they can be a problem and are very different from wonderful lacewings! Creatrix's advice is good. But also make sure they're getting enough moisture.

I too have constant problems with Lacebugs on my azalea. And yes, they are a completely different insect from the beneficial Lacewing.

I've had the best luck spraying with Safer's Insecticidal Soap, but even that isn't a cure-all.

I've also seen a lot of what looks like spider mite damage on azaleas this year. The same remedies apply.