A healthy lawn is your best defense against lawn diseases and other problems. But when the weather favors the disease more than your lawn, problems can occur. Reduce the risk of disease by keeping your lawn healthy. Mow high to encourage deeply rooted grass that is more drought tolerant and resistant to disease problems. Water early in the day so the grass leaves, blades, dry quickly and less water is lost to evaporation.
Apply the right type and amount of fertilizer at the proper time to limit the risk of disease. Regular fertilization, three to four times per year, encourages better results since most soils do not contain the essential nutrients for optimum growth. Avoid high nitrogen quick release fertilizers that promote lush succulent growth that is more susceptible to disease. Instead use a low nitrogen slow release fertilizer like Milorganite that promotes steady growth that’s more drought tolerant and resistant to disease.
Monitor lawns for Brown Patch when temperatures and humidity rise and grass remains wet for long periods of time. Infected lawns will have somewhat circular patches of thin light brown grass. Look for white cottony strands of fungal mycelium early in the morning on dew covered lawns. Check grass blades for small irregular tan spots with dark brown borders on the individual grass blades. Avoid heavy fertilization with fast release fertilizer in early spring and summer.
Look for dollar size to 6” diameter spots of bleached or light tan grass if you suspect Dollar Spot. Infected leaves have white lesions with reddish tan margins that often resemble an hourglass. Over and under fertilization, drought, water on the grass blades for extended time and mowing too low all increase the risk of this disease.
Closely examine lawns with a reddish hue to confirm the presence of rust disease. Rust infected lawns are covered with an orange or yellowish powder, the fungal spores, that can leave an orange residue on your shoes. Newly seeded and lawns weakened by inadequate fertilization and drought are most susceptible. Stay alert for leaf spot diseases that can attack lawns. Avoid excess fertilization and watering late afternoon and evenings.
Once you discover a disease, correct your lawn care practices to speed recovery and avoid problems in the future. Proper care and reseeding dead areas with disease-resistant grass varieties is usually enough to manage the disease. Be sure you need a fungicide before applying. These chemicals are costly, the results can be disappointing and when used improperly they can be harmful to pollinators and the environment.
Further speed recovery with a change in mowing habits. Continue to mow high but cut the healthy portions of your lawn first. Then cut the grass in the diseased areas. Once done, use a disinfectant to clean the mower blades then rinse with clear water. This along with collecting and disposing of clippings from the diseased areas of the lawn reduces the risk of spreading the disease next time you mow.
Provide proper care and monitor your lawn throughout the growing season. Discovering problems early means better results with less effort on your part.
Melinda Myers is the author of more than 20 gardening books, including Small Space Gardening. She hosts The Great Courses “How to Grow Anything” DVD series and the nationally syndicated Melinda’s Garden Moment TV & radio segments. Myers is a columnist and contributing editor for Birds & Blooms magazine and was commissioned by Longfield Gardens for her expertise to write this article. Myers’ web site is www.melindamyers.com.