The moth larvae is already on the seed when in the field. When you buy any kind of seed (even pellets) check for webbing. Looks like spider webs. Store all new food in a deep freezer. After 48 hours have 1 airtight container in the kitchen. Check all your supplies, like flour, sugar, etc. I remember even having moths inside a bag of almonds. Discard the old food every day. Discard it to the outside. You should be rid of the moths shortly.