Right On Cue: Dollar Spot Disease

Exactly like Dr. Bruce Clarke teaches, Memorial Day arrives and so does dollar spot disease.

Symptoms appear as round, brown to straw-colored spots approximately the size of a silver dollar. On short cut turf, the spots with advanced damage can become somewhat sunken. At taller cutting heights (greater than 1 inch), the damaged spots are larger and more diffuse.

Highly susceptible grasses will be the first to exhibit symptoms including annual bluegrass, creeping bentgrass (depending on cultivar), and perennial ryegrass. Tall fescue and most Kentucky bluegrasses will be more tolerant of this disease.

Cultural techniques that can suppress dollar spot disease include disruption of dew and guttation water in the morning and increasing N fertility (if it is low). Mowing early in the morning (disruption of dew) should also be helpful.

Creeping bentgrass entries in Dr. Stacy Bonos' evaluation trials that are highly susceptible to dollar spot disease appear in the image foreground.

Creeping bentgrass entries in one of Dr. Stacy Bonos’ evaluation trials that are highly susceptible to dollar spot disease (image foreground).

Dollar Spot Activity Flares Overnight

The high humidity of last night (28-29 May) caused dollar spot disease to escalate. Until last night, symptoms on unprotected susceptible turf were minor.

The cottony fungal growth (mycelia) of dollar spot, which is easily seen at early morning hours during wet humid weather.

Susceptible grasses grown under low N fertility will typically have [Read more…]

Disease Activity on Research Plots

Anthracnose disease has become very aggressive during the last week on our Poa annua research plots in North Brunswick NJ (see image below).

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