Red Thread Fungus

What is it???

As spring turns to summer and the climate seems to change daily, our turf grass is often faced with fungal diseases. An abundance of May rainfall and high June temperatures create a perfect environment for the common lawn nuisance, Red Thread Fungus.  Red Thread is a disease that affects the foliage of grass most commonly seen in late spring. High humidity and nighttime temperatures make it perfect for the spread of fungal spores in the lawn.

How can I identify Red Thread Fungus???

From a distance red thread fungus looks like tan or pink circular spots in the lawn.  Its name “Red” thread comes from the red or pink appearance on the leaf blade. To the common eye, the spots may appear to look like small dead patches of grass.  Red thread is most common in Kentucky bluegrass, rye grass and a variety of fescues. This is the exact blend of grass we see and use here in New Jersey in our residential lawns.

I think I have Red Thread, what do I do??!!!

Stay calm! While unsightly and undesirable, fortunately this fungus does not kill our grass. Crowns and roots remain unaffected so the grass can recover quite quickly with growth.  The application of Nitrogen to the grass and soil will help keep the rapid spread of red thread controlled. In higher problem areas we can apply fungicide to the lawn to rid the grass of Red Thread symptoms. Fungicide can control the disease for up to 21 days. We usually only see the fungus spread for a few weeks to a month in late May to early June so a single application is often the perfect cure.

In conclusion, Red Thread fungus is mostly just a temporary nuisance in our lawns. If untreated with nitrogen or fungicide, the disease can spread and weaken the grass, making the grass more susceptible to many other problems. The best way to keep Red Thread at bay is to continue a regular fertilization program. In every instance with lawn problems, early identification is key. If you see problems in your lawn please don’t hesitate to contact us. The sooner the better!


James Dinizo
Turf Club Property Control