I'm old fashioned, and believe that flea powder still has its place.
I use 5% carbaryl powder (such as Sevin) which you can get at the hardware store. It's used on tomato plants and is very cheap as a consequence, but it's also approved for use on dogs and cats -- see the label.
Sevin is a very good product for a dry space under a dog house or kennel bench where fleas might jungle up.
Sevin is required inside a vacuum cleaner bag, where flea larvae and adults are likely to end up after you vacuum.
Click here for a nice two-page sheet on dogs and fleas, and the various insecticides that can be safely used to battle them.
Along with flea powder, I also believe in flea and tick shampoo in season -- the cheapest stuff possible.
My dogs get washed after every hunt -- about three times a month. I have never had a problem with dry or itchy skin.
In the winter months, I simply use human shampoo on the dogs -- the same low-rent stuff I use on myself, and which get at the grocery store for $1.25 a bottle. The label, without a hint of irony, says it is called "Suave." All I know is that it works fine, and all shampoo is the same.
The notion that dog shampoo should be expensive or is "special" is pure marketing bunk. If a product is gentle enough and effective enough to be used on humans every day (twice a day some days in the summer), then it's perfectly fine for the dogs.
That said, a quick "dry dog bath" can also given if you are on the road hunting, and washing the dog inside a hotel room might be problematic
The trick here is to use a simple home-made powder or "dry shampoo," and to comb it in -- and out --thoroughly.
My recipe is to knock two-thirds of the baby powder out of one of the really small shaker cans they sell at the Dollar Store or in the "sample" aisle of the grocery store. Fill the now-empty shaker can with one third baby powder, one-third flea powder, and one-third corn starch or baking powder. Sprinkle the powder on the dog liberally, work it well, and then comb it out well after a few minutes (finish up with a flea comb).
This powder deodorizes (the corn starch or baking powder), kills fleas and ticks (the Sevin powder) , and leaves the dogs smelling fresh (the baby powder).
Make enough at one time to fill the small shaker can several times (store your extra powder in an old coffee can or jar with a label on it), and put the shaker inside your vet box where it can be accessed when you are on the road. Refill as needed.