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List of Lawn Info Necrotic Ring Spot is a root infecting fungus that affects Kentucky Bluegrass lawns. The disease survives in dead and decaying root tissues and is spread when the infected tissues are relocated by transferring soil, sod, or plugs of grass. Necrotic Ring Spot is a relatively new disease to our area. It was first noticed on a regular basis in the mid 1990’s stated that the disease was not found any further north than northern Colorado. Where it is possible to trace the history of an affected lawn there is a high incidence of these lawns showing symptoms of Necrotic Ring Spot three to ten years after being sodded. Numerous times the disease could be traced to imported sod from Colorado. Many times the sod source could not be traced. This is not scientifically proven finding, only observation. Most infected lawns were sodded over hard clay soils that have little or no organic matter and/or very little preparation. SYMPTOMS In the early stages, symptoms of Necrotic Ring Spot often appears as a small, scatted, circular, light gray to straw color patches. As the symptoms progress, these patches become sunken and appear as rings or arcs of dead grass. Often tufts of healthy grass remain in the center of the ring producing a “frog eye” pattern, hence the common name Frog Eye Disease. The disease spreads in April and May with the symptoms appearing when the turf is allowed to go under stress in July and August. Symptoms may increase in severity one season and lessen in another season depending upon grass stress. CONTROLLING NECROTIC RING SPOT The disease symptoms can be suppressed by encouraging a healthy turf with minimum stress. The following cultural practices need to be addressed to keep infected turf as healthy as possible.
CHEMICAL CONTROL Chemical control works only in combination with cultural controls. Rubigan applied spring and fall for two consecutive seasons is rated the number one control, but is only registered for commercial turf. Eagle, Banner, Maxx, and Cleary’s 3336 applied as a spray or Eagle granules applied as a spreadable, work well if applied in April or May and again in October for two consecutive seasons. All of the above fungicide applications need to be irrigated in. LONG TERM SOLUTION Fine leafed turf quality perennial rye grasses are not affected by Necrotic Ring Spot. Some of the genetically improved varieties of Bluegrass, e.g. Midnight, American, Unique, Rugby II, Odyssey, Award, show a high degree of resistance to Necrotic Ring Spot in the National Turf Grass trials. These Bluegrass varieties also show outstanding performance in the Rocky Mountain Trials. The above grasses should be used in inter-seeding or re-establishing Necrotic Ring Spot infested turf. Aeration is the process of mechanically removing small plugs of thatch and soil from the lawn. The holes act like mini pipelines to move water, air and fertilizer to the root zone. The turf roots will then have more room to grow in the loosened soil and will spread out toward the pockets of water and nourishment. The soil plugs will dissolve during rainfall and watering enabling the soil to mix with the thatch layer, helping it to decompose and break down. Aeration leads to stronger root systems, better soil structure and a reduced thatch layer giving you a thicker, greener, healthier lawn.
Expectations with one application of lawn weed control. We will only control standard lawn weeds that are present at the time of application. Some perennial weeds like thistle, creeping jenny, clover, etc. will require additional treatment.
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