Fungal infection that appears mostly on golf courses where there is low cut bentgrass, but it may also attack bluegrass and fine fescue. Growth of dollar spot occurs more often in periods of leaf wetness and temperatures between 60 and 85 F.
Dollar disease first appears as tiny yellow spots on the blades of grass. As it enlarges, the discolored areas may have the shape of an hourglass on the grass blade. Eventually, the entire leaf blade will yellow and areas may become as large as 2-3 inches in diameter. When morning dew is present, you may note a fine, white cobweb of mold to areas.
Again good cultural practice should greatly reduce the chance of dollar spot occurring; adequate balanced fertilizer and watering in the morning hours so blades don't remain wet for long periods.
Fairy ring is a fungi infection of the lawn. It may be caused by buried organic material such as an old tree stump, large dead roots or even lumber that has been buried during the construction of a house. The fungi that cause the ring prevents water from infiltrating the soil and thus causes the death of the grass due to a lack of moisture.
It first appears as either a growth of mushrooms or a circular pattern of very dark green grass. The ring of dark grass will eventually die leaving a circle of brown dead grass.
Prevention includes removal of any old stumps or roots and making sure lumber scraps do not get buried into the lawn area. Treatment is mostly aimed at improving water penetration to the area. Aerate the soil that is infected and at least 2 feet out from the ring. If there is thatch buildup, remove thatch. Water heavily and add a wetting agent such as soap to improve water penetration to the area. If the disease is severe, you may need to remove the sod and soil underneath, fill in with uninfected soil and reseed.
This is a fungal disease that is especially bothersome to bluegrass, bentgrass and tall fescue. Hot, humid conditions when grass has been drought stressed make lawns more susceptible as well as excess nitrogen.
Fusarium blight can appear in circular patches or elongated streaks of grayish green that can be from 2-6 inches in diameter. Grass in the center of these areas may survive giving the areas what is described as a donut or “frog-eye” look. As the patches die, they will progress to brown and then straw colored.
Plant bluegrass with a mixture of perennial ryegrass, prevent drought stress with good watering techniques, control thatch as needed and fertilize appropriately with a balanced fertilizer.
This fungus attacks many plants including ornamentals and garden crops. Bluegrass is the most susceptible of the turfgrasses, but it may be a problem on fescues also.
It appears as a grayish white powdery or cobweb like growth. it will be seen primarily on the upper sides of leaves.
Water in morning hours to prevent leaf blades from sitting wet for long periods. Reduce shaded areas and increase air circulation. Usually cultural practices will alleviate problems, but if needed, may spray with gardener's sulfur.
These two fungal diseases may show similar symptoms, may or may not occur together, but red thread is usually the more common and more severe. All turfgrasses are susceptible, but perennial ryegrass is the most susceptible. Creeping red fescue is also fairly susceptible, but other fescues are more resistant. Areas with prolonged cool weather are the most susceptible.
Circular or irregular patches from 2 inches to 2 feet in diameter appear and the grass quickly dies. Red thread will have pink to pale red threads. Pink patch areas will become covered with a pink or red gelatinous crust. Grass blades die from the tip back.
Rarely do you need to treat this disease with fungicides. Often the problem is a lawn low in nitrogen. Apply balanced fertilizers and practice good cultural lawn care.
Another fungi that may appear on all types of turfgrass and is most prevalent after periods of heavy rain or over watering.
This fungus appears as ash gray, blue-gray, black or even white and slimy, but as it dries, may look powdery. If infestation is high, the grass may yellow slightly.
Slime molds generally do not harm the grass, but give it a bad appearance. As the lawn dries, it will go away by itself, but you may rake it away also.
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