Disease Control

Grass Diseases

Brown Patch

One of the most widely spread diseases that can affect almost any cool-season turf lawn in many parts of the country is Brown Patch. When nighttime temperatures start hovering around 65 to 70 F in early summer, this disease can wreak havoc on tall fescue, Kentucky bluegrass and perennial ryegrass. While it is relatively easy to identify (see brown patch symptom photo above), it can sneak into any turf stand and by the time you notice, it will be at significantly high levels. Fortunately, the solutions to control brown patch are numerous and effective. Fungicides are the best options for controlling Brown Patch.

Red Thread

Red Thread occurs mainly in the early summer, particularly during unseasonably wet conditions.  Red Thread appears as brown or tan patches, however close inspection reveals reddish or pink threads growing from the grass blades. Costello Landscaping will apply a broad-spectrum fungicide, this product kills the active fungus while helping prevent the spread of the disease for up to 4 weeks. A lot of us New Englanders love a lawn full of Kentucky Bluegrass. Sometimes when a lawn is heavily Bluegrass, the disease Summer Patch literally eats it up! If your lawn is covered with irregular brown patches and upon further inspection you see: Wilted, irregular circles of grass up to 2” in diameter. The outer edge looks yellowish. Grass blades are dying from the tip.

Diseases of Trees


Fireblight (seen here on an affected Crabapple) is caused by the bacterium, Erwinia amylovora. It is a serious disease that affects new leaves, fruit, flowers, and stems of over 75 species of trees and shrubs in the rose family including: apple, crabapple, hawthorn, pear, pyracantha, cotoneaster, spirea, flowering quince, and mountain-ash. You can recognize the symptoms in the foliage & flowers:

  • Flowers appear water-soaked, then droop and shrivel, turning brown or black. 
  • Leaves brown or black and hang downward. Trees with multiple, infected shoots may appear scorched by fire.


Anthracnose (seen here on a Dogwood) Anthracnose caused by the fungus Discula destructiva is a potentially fatal disease that attack trees such as Sycamores, Dogwoods, and Maples causing significant stress and potential death. You will first see symptoms in the foliage:

  • Infected leaves are often distorted, cupped or curled.
  • Tan to brown irregular shaped spots or blotches on young leaves.
  • Severe infection can result in leaf drop in spring.
  • Leaf symptoms are often most severe on the lower and inner branches of the tree but may progress up through the canopy.

Beech Leaf Disease

Beech Leaf Disease was recently found in August 2019, a new disease that affects beech trees was detected in Connecticut for the first time, along the Mianus River between Stamford and Greenwich. The symptoms on the leaves are very evident. Tell-tale is readily apparent, interveinal discoloration, dark-green early in the season and then yellow later on, as the season progresses. If you think you may have found Beech Leaf Disease, please report it to Dr. Marra at Robert.Marra@ct.gov.

Call us at (860) 747-1771 or contact us online if you have any questions!

Serving Central Connecticut and surrounding towns:

  • Middletown
  • Barkhamsted
  • Goshen
  • Harwinton
  • Northwest Harwinton
  • Litchfield
  • Bantam
  • New Hartford
  • Plymouth
  • Terryville
  • Thomaston
  • Torrington
  • Watertown
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