What kind of large flies? Around your garden (where they are probably beneficial insects) or your home?

Haven't seen any grasshoppers yet. The birds will have to get them, though. I expect the grackles will just love them!

Hi rhizo,
The flys are called cluster flys, they are 3 times bigger than the common house fly. I have mulched my flower beds with grass clipping and they are thick on the clippings.
You say they are benefical.Do they eat other insects?
We don't have many birds here for lack of trees so the grasshoppers are eating the leaves of some of my plants,I need to get rid of them but don't want to harm the good insects. What would you recommend for a bug spray?
Any advice would be helpful.
Thanks.

You live in a part of the country where grasshoppers can become a true nuisance, I understand. I wish I could offer you some help, but this is beyond any experience of mine. I can't use or be exposed to most pesticides due to a chemical exposure several years ago that permanently damaged my liver function.
Do you live on or near a farm? Cluster flies, as you have identified them, are often associated with the rich soils of farmland or other properties where organic materials been introduced to enrich the soil. This means more WORMS, which is the only thing that the cluster fly maggot parasitizes on.

Good luck! I hope some others will jump in here and come up with some helpful solutions.

Here is a link that might be useful: Cluster fly control ?

I read on another forum (but can't find it now) a recipe for grasshoipper repellent. Catch some grasshoppers, put them live into the blender, strain the juice and dilute. Spray this around your garden. Apparently, the hoppers release a hormone as they are destroyed that lets other hoppers know there is danger. They won't come around if they sense the hormone.

Made some sense to me.

The Nuclear Polyhedra Virus is made by taking some of the target insect, whizzing it in a blender with some water, straining it, and then spraying it around where the target insect is. The theory is that all insects have a means of destruction on or in their systems and this process resleases enough of that virus to control the buggers

Here is a link that might be useful: Nuclear Polyhedra Virus

My favorite bug spray: Water.

My favorite bug spray- Cutter's Deep Woods- the more DEET the better! I'm a mosquito magnet and not planning to procreate.