Sorry that your post hasn't gotten any response for a few days. I think that the problem might be that no one can really give a good answer, because there isn't much research into this question. I've never even heard of phenethyl proprionate being used as a mosquito "fogger". I doubt that it would have much impact on pollinators, but I also don't know whether it's going to be very useful for your mosquito population, either.

Mosquito control via insecticides can be separated into two broad categories - adulticides and larvicides. Spraying a mist or fog of the chemical, you're going to be targeting the adults. The traditional chemicals used for this may work as a "knockdown" of the adults which are currently in the area (directly contacted by the product), and/or by contact with the pesticide residue on the foliage that they rest on.

If you're just treating your own property, then direct knockdown isn't going to do much - the surrounding population will just move right in. (that's a big difference from treating for a relatively immobile type of pest like ticks). But I don't know whether the product will have enough of a residual effect on mosquitoes that come to rest on the foliage to have a significant or lasting effect. I can't say that it won't, but I'd like to see some evidence for it.

If you have a body of water on the property that is a source for mosquitoes, then using a Bt product to kill the larvae there would probably be both less expensive and more effective.

Yes, most of the webpages I looked at stated there was no data available yet for this product.

There is a very long list of insects that this product is labeled to control. The beneficials are never listed on a chemical label, only the pests. However.....it's only common sense to draw the conclusion that something listed for carpenter bees will also harm other bees (for example) .

It works by direct contact but I couldn't find any research about what it does to nectar or pollen.

Pesticide labels can be confusing for some. Remember, if something is labeled to control a long list of pests......it will also be harmful to critters that we don't want to harm. This is also true for the 'organic' products.

I really, really don't like broad spectrum mosquito abatement products. Sometimes, I think that the applicators might even be clueless about the damage that these products can cause.

Like saccharum says, larvicides are the way to go whenever possible. That and PP (personal protection) .

Yeah, the unfortunate fact is that if you ask a pesticide application company how to deal with a pest issue, they'll generally recommend spraying a pesticide - regardless of whether it's necessary, whether it will work, or whether there are other methods which may work better. Often they have just a few broad-spectrum products in their regular arsenal, which they'll use for just about everything. It's true for companies that do lawn care, tree care, organic or conventional, etc.