Soil-dwelling critters chew on plant stakes if bamboo or woody. To be expected.

If iris root is chewed, that's completely different & more important.
If it smells fishy, perhaps it's too wet?

Please post a picture,

Where do you live? Closest city and state

Urban, subutban or rural?

Close to water or woods?

The United States is a very big country with many different environments, growing habitats. Knowing where in this immense country you are would be a big help in knowing more about what the problem might be.