Although NRS thrives in our arid climate and weather conditions, it can be controlled by the use of resistant varieties, good turf management practices and fungicide applications.
What you need to do to prevent lawn diseases
Mowing: The highest setting on your lawn mower will help shade the soil, keeping the roots cooler in the hotter months. A taller lawn height also conserves moisture and promotes lateral growth to thicken the lawn. A sharp mower blade will also improve the general health and appearance of the lawn. (2 1/2” to 3” mow height)
Watering: Necrotic ring spot almost often occurs in lawns receiving too much moisture, however reducing your watering practices is not the answer. The goal of lawn watering is to effectively wet the soil to a depth of 6 to 8 inches, without water puddling on the soil surface. During the growing season we recommend one 15 minute watering in the morning, and one 15 minute watering in the evening. During the spring and fall, watering two days per week should suffice. During hot and dry summer months, watering 3 days may be necessary.
Reseeding: Often over-seeding with a blend of disease resistant seed will help re-established your lawn in damaged areas. We recommend a blend containing perennial ryegrass.
Fertilizer: Abundant soil fertility also encourages NRS development. Withholding some nitrogen fertilizer, while making the lawn just a bit less lush, will discourage necrotic ring spot. The secret to good NRS management is to provide a balanced fertilization regimen, which avoids peaks and valleys in nutrition. That is, apply fertilizer that slowly releases nutrients into the grass plant. Swingle offers two different fertilization programs designed for necrotic ring spot management.
Organic based fertilizer
This fertilizer is primarily derived from organic sources including alfalfa, blood meal, cottonseed meal, urea, and ferrous sulfate. Applied five times during the season, this fertilizer provides readily available nutrient and also includes a slow release component. Biological stimulants are also included to increase microbial activity. Soil microbes break down the thatch layer into useable nutrients for the grass – it also increases the soil biodiversity.
Time released engineered fertilizer
This fertilizer is applied once during the season – either in the spring or fall. Caliber Cote releases nutrients when the soil is moist. The slow release of nutrients helps the turf grow steadily – promoting healthy root growth, while maintaining a green lawn.
Results: We do not guarantee control for Necrotic Ring Spot. We have found, however, that improved lawn care practices can greatly reduce the scarring that occurs. Following our recommendations for both lawn care practices and treatment will help suppress NRS damage. In turn, this will encourage new growth which will fill in old NRS scars and improve your lawn’s health and appearance.