By Jim Murphy

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.

Cottony fungal growth (mycelia) of dollar spot, seen at early morning hours during wet humid weather.

This morning dollar spot mycelia was so profuse on this low maintenance turf that it looked like frost.

Susceptible grasses grown under low N fertility will typically havethe greatest damage from dollar spot. Annual bluegrass (Poa annua) is highly susceptible to dollar spot disease. In fact, you will often see annual bluegrass as the grass species with the most dollar spot damage in a mixed stand of grasses. Some varieties of creeping bentgrass have better tolerance to this disease and should be considered when selecting a variety. Colonial bentgrass is generally more tolerant of dollar spot than creeping bentgrass, although differences among colonial bentgrass can also be seen. The variety, Capri, had less disease this morning compared to older colonial bentgrass varieties. Perennial ryegrass is another species that will often be infected by dollar spot before other grasses, especially when is managed with low N fertility. Kentucky bluegrass can also be affected by dollar spot but many varieties have good tolerance to the disease.

Source: Read More on the Rutgers Turf Blog

By Jim Murphy

Several weeks ago the cool wet weather brought on some red thread disease activity that has increased over the past 4 to 5 days. Turfs under low maintenance, particularly low nitrogen fertility, have been the areas with the greatest amount of red thread. This disease has been active on on slender and strong creeping red fescues, Chewings fescue, velvet bentgrass, perennial ryegrass, and tall fescue this spring. [Read more…]

By Jim Murphy

During the last couple weeks, we have seen crabgrass emerging from open turf areas that were previously infested with crabgrass. Crabgrass emergence will probably occur later than this on better maintained turfs with a dense canopy.

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By Jim Murphy

There are numerous elite varieties of Kentucky bluegrass (Compact Types) that have excellent tolerance of leaf spot, summer patch, and stripe smut diseases. Many varieties produce a very attractive, dense, compact (low growing) turf with dark green color during the summer.

However, many of these Kentucky bluegrass varieties that are grown and sold as sod have the growth characteristic of long winter dormancy and slow spring green-up. The cool dry weather of this spring has certainly exacerbated this growth response. Full green-up of these varieties typically occurs by mid- to late-May.

Practices that hasten spring green-up of turf include fertilization with moderate amounts (0.4 to 0.7 pounds per 1,000 square feet) of water soluble nitrogen (WSN) and covering the turf with a growth blanket early in the spring (March and April).

Perennial ryegrass and tall fescue will often green-up several weeks earlier than these Compact Type Kentucky bluegrasses. Perennial ryegrass typically will have the earliest green-up.

Of the fine fescues used for turf, creeping red fescue will green-up earlier than Chewings fescue and hard fescue will have the slowest spring green-up. Green-up of creeping red fescue is relatively early and not too different from perennial ryegrass.

Source: Read More on the Rutgers Turf Blog