By Richard Rees
What does it look like?
Take-all patch is caused by the root-infecting, soilborne fungus Gaeumannomyces graminis var. graminis, a serious disease that has the potential to destroy large amounts of turfgrass and has proven to be very difficult to control.
Symptoms of take-all patch are most prevalent in late spring, first appearing as small, water-soaked areas of turf. As the disease progresses, yellowing circular or irregular-shaped areas continue to spread up to two feet in diameter. Generally, these patches form a circular pattern as the fungus grows outward. Diseased plant roots become so brown, rotted and damaged that the stolons are easily removed from the ground.
Host material and range
Cool, moist conditions favor take-all patch infections. In the northern United States, bentgrass is highly susceptible, and, therefore, golf course putting greens and bentgrass fairways are most likely to suffer from the disease. Some bluegrasses and fescues may become injured, however these turf species most often survive as they do not typically sustain serious infection. In the South, take-all patch infects St. Augustinegrass and in some cases can also damage Bermudagrass. During the summer months, when turf is particularly stressed and weak, infected turf will continue to decline.
If left uncontrolled, take-all patch has the potential to destroy large amounts of turfgrass. Regrowth in infected areas is extremely slow and often unsuccessful, as the new growth quickly becomes re-infected.
To lower the risk of infection, implement a balanced fertility program. If necessary, lower the pH level of the soil with either sulfur or an acidifying fertilizer. Avoid lime and alkaline fertilizers. Aeration, proper irrigation and topdressing will also aid in promoting healthy root growth and development.
Controlling take-all patch is very difficult, and there is much to learn about this disease. According to Dr. Richard Latin, professor of plant pathology at Purdue University, certain acropetal penetrant fungicides may be used to suppress take-all patch outbreaks. Always follow product label rates and instructions.
Fungicide application timing and delivery will affect product performance.
Fungicide treatments should be applied only when the pathogen is active. Research shows that applications in early to mid spring and again in early fall are most effective.
What can you do?
Good cultural practices, especially during the stressful summer months, can reduce the risk of take-all patch. Water wisely, fertilize properly, remove thatch regularly and, if necessary, increase mower height and redirect traffic to reduce compaction.
Richard Rees is product development manager — fungicides, Bayer Environmental Science. For more information, visit www.backedbybayer.com