Pest description and crop damage Shiny black beetles about 0.09 inch long. Adults seeking pollen damage flowers and prevent seed set. Browned flowers are unattractive to pollinating insects. This insect is primarily a pest of red or white clovers blooming in July. Beetles usually are active in clover fields mid-July through August.
Prebloom chlorpyrifos or bifenthrin spray for clover aphid also helps suppress nitidulids.