Adults.

Leaf notches on edge of clover leaves indicate adults CRW feeding damage. This damage alone will not kill clover because it is bred for defoliation, but indicates the presence of the pest and warns of more serious damage occurring below ground.

Larvae. 

Younger larvae damage nodules leading to reduced N fixation.

Older larvae feed on roots and stolons which reduces clover content and persistence. This damage can lead to total clover loss and less N, so the pasture becomes less productive.

This picture shows severe adult feeding. You may see fewer notches, so check for other signs of damage too.

Young larvae feeding damage on clover nodule. Older larvae damage clover stolons.