What is this bug/cocoon?

[Nicholas]

In the Pacific Northwest US (Oregon), in the valley. Found this funky looking corn leaf, found these little cocoons (?) inside of it. Anyone know what this is?

 

[Chuck]

I think it is the larval stage of the corn leaf roller which will turn into a caterpillar which will start eating the plant. Not to be confused with the corn ear worm which eats the corn from the ear but not the plant itself