Malt is agricultural product. Weevils and moths like it. Moisture likes it too. The old blog post at this URL treated bugs as a seasonal surprise. They are a storage design flaw.
Keep uncrushed malt sealed, dry, and away from pet food. Crush close to brew day when you can. If you find insects, you decide whether to salvage or discard; this page will not invent a health statistic for that choice. Clean the cupboard. Do not pour a contaminated bag into the good bin.
A freezer can slow insects in small packs. A damp shed can undo a malt mill’s work by staleing the grain before the bugs even arrive.
This is not a pesticide manual. It is a reminder that all-grain starts in the pantry.