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Yellow Patch

What is Yellow Patch?

Yellow Patch

There are many microorganisms in your lawn that are beneficial, aiding in thatch decomposition. However, there are also a few harmful organisms that are parasitic forms of plant life called fungi. Fungi live in soil, thatch and dead leaves within the lawn all year long. These fungi feed on the grass by drawing nutrients from the plant and destroying the plant cells. Diseases spread, in the form of spores, throughout your lawn by wind, air, water, and traffic. The disease may re-appear from year to year if certain conditions are favorable. As a general rule, areas that have been prone to disease problems in the past will at some time, if not yearly, have the same problems again. Yellow Patch disease or cool season Brown Patch can affect Kentucky bluegrass, Perennial Ryegrass, Tall Fescue, Bermudagrass and Zoysiagrass. The disease is most prevalent during the late fall, winter and early spring when temperatures are cooler. It causes the turf to become patchy with the rings of patches that are yellow, light brown, or reddish-brown in color and measure 5 inches to several feet in diameter. Damage is usually superficial but thinning can occur with prolonged periods of wet weather in the late winter early spring.

Conditions Favoring the Disease

Yellow Patch is most prevalent from late fall to early spring when temperatures are less than 60*F (16*C). It occurs in areas that receive more than 10 hours of leaf wetness for several days in a row and on turf that has excessive thatch and high nitrogen levels. Poor mowing habits like a dull mower blade can increase the probability of Yellow Patch by leaving the turfgrass blades exposed to the disease.


Using a slow-release fertilizer to ensure moderate amounts of Nitrogen will help in reducing the chance of Yellow Patch. Reducing the leaf wetness period will also help prevent Yellow Patch. Nighttime watering can increase the leaf wetness period and lead to disease. Follow Weed Man's proper watering instructions! Allow for better air movement in order to help dry the lawn when moist. Remove excess thatch through regular aeration will also help alleviate compaction and improve drainage. Ensure that when mowing the lawn is mowed at a high level when dry and in the morning allowing for the grass blades time to heal. Early evening mowing will increase the chance of Yellow Patch as well as a dull mower blade. 

Your Local Weed Man Dealer Can Help

You're locally owned and operated Weed Man dealer is here to help. Weed Man's turf specialists can recognize Yellow Patch disease and make recommendations to help your lawn. Weed Man's specially blended slow release fertilizer applied at the right time is the first step in preventing Yellow Patch. Weed Man's fertilizer helps create healthy turf by slowly feeding the lawn as it needs it encouraging deep rooting systems. Your local Weed Man dealer will also be able to advise you on any other treatments or cultural practices that may be necessary to help your turf remain healthy and vigorous.

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