Ugh!! I had this problem years ago when I first moved to Texas. We had a lot of pets and were purchasing all their food and litter from the local feed store. When I started noticing the moths (or some type of flying bug) and the weevils, I went into an exterminator's shop and they told me what to do and I purchased a can of organic spray which was quite pricey. They told me to put the food in the freezer and then to move it to an airtight container later. I was reluctant to do this as I thought it would make their food soggy, but I was quite surprised when it didn't! I bought lots of containers (walmart, which is the cheapest, then the name brand stores, such as the container store, etc.) that stored and stacked efficiently. I never had the problem again. But I still keep all of my pet items in airtight containers and my sugar, flour, etc. as well. Good luck! Oh, and I buy my dry dog food in huge bags (40 or 50 lbs.) and store it in the orginal bag in an airtight trash can (walmart) in my garage. No problems at all!!