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What is it?

A lawn disease caused by fusarium species fungus organisms, which are active during weather, which is sunny and 75° to 100° F.

What does it look like?

Patches of grass lighten in shade from green to straw colored beginning in June and commencing in August. Hotter spots like those along cement or driveways are usually affected first. The patches are streaked, crescent shaped and can go up to several feet in size. The middles will often remain green which is known as a “frog eye” pattern.

How does it manifest?

Lush dense growth of primarily bentgrass or Kentucky Bluegrass or lawns with other grasses that have been stressed by drought, dry winds and heat and a pH below 6.0 are most susceptible to the disease. Fungus can survive the winter, so even though cool fall weather brings new grass to dead areas, the disease may recur the following year when temperatures rise again.

What can you do about it?

Rake out dead grass and reseed with a mixture of 20 percent perennial ryegrass and 80 percent bluegrass, or a similar resistant mix. The following year in May, before disease conditions are optimal, treat the entire lawn with a benomyl or iprodione containing fungicide for a total of three treatments at 14 day intervals. Water thoroughly both before and after application. Although this will help stave off fusarium blight, once it has occured it is very difficult to control or remove completely.