Red Thread Lawn Disease

Red Thread Lawn Disease – A Serious Disease, But Not Too Serious

One of my favorite diseases is Red Thread as it is one of the easiest disease to identify.  What makes it so is the pinkish-red color that is an indicator of its activity.  Upon careful examination, you may see a thin antler-like structure protruding through the tip of the leaf blade, which may resemble a tiny thread.  This is how the disease gets its one of its names – Red Thread.  There is a similar disease, Pink Patch, that develops masses of pink fungal hyphae in the thatch or on the leaf blades.  Both of these diseases can occur at the same time.

Red Thread can develop in both spring and fall, but it is generally considered a late spring disease.  Temperatures that favor its development is between 40 to 70 degrees with long evening dew periods.  It has long been associated with weak, under-nourished turf, it can quickly develop even on well managed turf as well.  The spores of the disease remain in the thatch during none-active periods and will begin to develop when conditions are right.

The damage that Red Thread causes can be unsightly, but the symptoms are temporary as the disease does not affect the crown or roots.  Many times, a supplemental lawn fertilization will help the turf “grow out” of the disease and it will return to normal in a short period of time.  Disease control treatments are usually not necessary as once the disease activity is seen, it is basically run its course and the turf will recover on its own.  If it is a re-occurring problem, a spring application of a disease control material may be recommended.

Why Does My Lawn Have A Disease?

Sometimes it is difficult to predict lawn disease pressures, but understanding how a disease gets started is an important part of the process.  Disease spores are common in many lawns and can persist for years before conditions are right for the disease to become active.

Just like there is a fire triangle that describes the elements that are required for a fire to start – oxygen, fuel and ignition – there is also a disease triangle of the three factors that need to be in place for a disease to develop.  First, the disease causing organism needs to be present, which often is available in the lawn or landscape.  Second, you need the host plant that is susceptible to the disease.  Third, you need the proper environment, which encompasses many different weather factors such as cool and wet, cool and dry, warm and wet, warm and dry, hot and humid, hot and dry, the list goes on and on.

Other factors can also influence disease development, especially if it puts the plant into some type of stress.  These include mowing too short, too much water, too little water, too much fertilizer, not enough fertilizer, as you can read; this list is almost endless as well.  The one thing that brings it all together is time.  The environment has to exist for a long enough time for the disease to develop and invade the host plant.  This time period fluctuates greatly from a couple of hours to several days.

Unfortunately, even with the best lawn care diseases can still develop.  A lawn that is well-maintained will be better able to fight off infection and recover faster after the disease has run its course.