Optimum growth of cool season grasses occurs within the temperature range of 60 to 75°F. Yesterday, the New Brunswick weather station indicated that soil temperature at 2 inches exceeded 75°F for more than 12 hours and peaked at 82°F.

This doesn’t mean that grasses will soon be dead. But it is a signal to be watchful for summer stress problems.

Summer stress is often a combination of multiple stresses. Localized drought, ponding of water, diseases, insect pests, poor culture (mowing, fertilization, and irrigation) and other stresses combined with high temperature stress can challenge the health and persistence of cool season turfs from now through the end of summer. It is important to avoid situations that compound too many stress at the same time. [Read more…]

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.

Most landscape lawns, sports turfs, and golf course surfaces should have reached full green-up but there will be some exceptions. The major exception to this is zoysiagrass turf.

Zoysiagrass will not begin green-up until mid- to late-May. Although not as slow to green-up as zoysiagrass, fine fescue will be slower than perennial ryegrass and tall fescue. Many of the Kentucky bluegrass varieties that are commonly used for sod production will be slow to green-up in the spring.

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Brown Ring Patch (aka Waitea patch) is starting to show up on golf course putting greens at this time.

This disease is caused by the fungus Rhizoctonia circinata var circinata and typically develops during warm weather from April through June. Symptoms start as small yellow rings (0.25-2 inches wide) with green grass in the center and can ultimately reach a foot or more in diameter. The yellow rings can turn an orange or brown color as the disease progresses. [Read more…]

The leaf spot phase of this disease, caused by the fungus Drechslera poae, is apparent on susceptible Kentucky bluegrass turf at this time.

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