I also would like to know what we can do to prevent wasps from building small nests on our porch overhang. Is there any preventative stragegy, or chemical spray that can be used?

 

My dad and I have them around our homes. Im not sure what to do to prevent them, but i can tell you what he does to kill them. He sprays a brake fluid on them. As soon as the fluid hits them they are dead! Not sure what kind he uses. but any kind may work.

 

tmadsen probably means brake cleaner. Yes it will kill them fast. You can use any kind of wasp spray, the longer the treating distance the better. Then you must take down the wasp nest, if it is paper wasp. Mud daubbers are more difficult. There is no easy way to control these. You will have to spend time out side and watch what they do, and stop them as they get started. I forgot wich wasp does what. One places a spider in nest before planting egg and the other uses caterpillars. Try to get the out side of your house sprayed and the shrubs with a pesticide.I'm not sure if they remember where they were born and return or not. If so interrupt their life cycle.

 

Brake/Carb cleaner will kill wasps faster than anything I've ever seen. It also kills the 'scent', that guides other wasps back to the nest.

A few problems with it though..
It's a pretty direct stream, so you have to right on target to hit all the wasps.
It can remove paint or discolor finishes.
You do NOT want to get it in your eyes, so be sure to spray downwind.
It does nothing to 'hold' the wasps on the fringes and keep them from flying at you.

I've tried the foaming wasp sprays from Basic Solutions (big box store), and it works very well. While it doesn't kill as fast as brake/carb cleaner, the foaming action traps the wasps to the insecticide until they die.

 

Mud daubers are basically harmless and don't sting unless you actually handle them. We had a new nest above our front door for a couple of years in a row. I would just wash the mud off in the fall. Sadly we don't have one this year. These are considered beneficial insects as they prey on many bad bugs and pollinate flowers and fruit. Here's some info and pics.
http://www.ipm.iastate.edu/ipm/iiin/bmuddaub.html
http://www.pollinator.com/beneficials/trypaxylon_politum.htm

Black and yellow mud dauber:
http://stephenville.tamu.edu/~fmitchel/insects/bymudd_s.htm
http://stephenville.tamu.edu/~fmitchel/insects/bymudd_t.htm

Blue mud dauber:
http://www.wingwatchers.com/images2/bdaub.jpg

Pipe Organ mud dauber:
http://bugguide.net/node/view/7276

Newt

 

The best time to knock down wasp nests is at dusk after they have gone to bed. There are commercial wasp sprays that have a stream of several feet. To be on the safe side, wear long pants and long-sleeve shirt.