This is a fungal disease that attacks lawns that are highly exposed to the sun and are made up of either Kentucky bluegrass, red fescue, or bent grasses. Fusarium blight will cause small brown rings to appear in early summer. To remove the fungus, begin by heavily soaking your lawn and avoid frequent light soakings. Then, dethatch and apply lime treatments to your lawn to avoid acidic soil. Finish up by applying high-Nitrogen fertilizers.