Granules for pest control are generally a dissolvable solid that has been embedded with an active ingredient. You apply them with a spreader and lightly water them with your garden hose.
So what is the advantage as a home owner? Simple answer – equipment. You don’t need to go to the store and buy tanks, hoses, pumps and nozzles to spray a liquid, or try to use that little spray mechanism that comes on the mixed ready-to-use store-bought liquid formulations. Another area they have an advantage is in higher moisture areas like lawns and heavily landscaped areas that retain a lot of moisture (what I’ve found living in Arizona or at least the Cottonwood Area that we do not get a lot of areas of higher moisture in the High Desert).
So what are its limitations? It can be a little difficult to treat cracks and crevices with a granule and they can be a little messy. Always wear the proper safety gear when using them as with any pesticide. You can find safety information on the label.
Some popular active ingredients used in insect granules is Lambda Cyhalothrin, Deltamethrin, Bifenthrin, Cabaryl and Permethrin. The common trade names you will see in the stores are Sevin, Ortho Bug B Gone, Demand G, Cyonara LP, Deltagard, Bifen LP, Talstar PL, All Pro and Martin’s Lawn & Perimeter to name a few.