Miller moth

Miller moth is a common name for the adult army cutworm moth, a North American insect. It gets its nickname from the fine, dusty scales on its wings that resemble mill dust or flour. These moths are particularly famous for their massive seasonal migrations.

These moths undergo a mass seasonal migration from the eastern plains to the Rocky Mountains during the late spring. They make this journey to escape the extreme summer heat and find nectar-rich flowers in the cooler mountains. In the fall, they migrate back to the plains to lay their eggs.

The adult miller moths are generally just a nuisance when they invade homes, but they do not bite or destroy clothing. However, in their larval stage as army cutworms, they can be severe agricultural pests that damage wheat and alfalfa crops. As adults, they actually serve as an important food source for bears in the Rocky Mountains.

The intense swarms of miller moths typically last for a few weeks in the late spring, usually around May or June. The duration depends on the weather and how quickly the moths can complete their migration to the Rocky Mountains. Once the summer heat sets in, the massive invasions in plains states like Colorado usually subside.