Yes, Talstar P (Talstar One) is labeled for gnats and roaches. You will use 1 fl. oz. per gallon of water. This can be sprayed around the perimeter of your home, on trees, bushes, broadcast across your lawn, etc. It cannot be sprayed on any type of edibles or area where animals would graze.
We would also recommend mixing the Talstar P (Talstar One) with Gentrol IGR. This will stop the roaches from reproducing for up to four months.
Diazinon was outlawed over 10 years ago, and it is too bad because it was a great product. Unfortunately, the over the counter products do not even come close to the effectiveness of Diazinon. However, our professional products do! We sell the same professional products used by professional companies that cannot be sold over the counter. Our most popular product is Talstar P. It is a general use insecticide which can be applied inside and outside, is odorless, is labeled for over 80 different insects, and can last up to 90 days in between treatments. Please take a moment and read some of our over 50 customer reviews about how well Talstar worked for them.
Termidor SC around the perimeter of the home would be better than Talstar P. Termidor will have transfer effect so can help to eliminate the entire colony whereas Talstar P will only kill the ants that contact a treated surface. It can be applied twice a year or four times a year outside depending on the rate. This link can explain.
You should caliberate your sprayer to disperse 1 fl oz per gallon of water per 1,000 sq ft.