College of Agriculture & Natural Resources

• Creeping Bentgrass

  Creeping bentgrass is a spreading cool-season perennial grass that is commonly used for golf course greens, tees and fairways. Like other grasses, bentgrass can be considered a weed when it is present in another species.

• Gray Leaf Spot

  Gray leaf spot is considered a problem on primarily perennial ryegrass and St. Augustinegrass. The disease first appears as tiny brown spots that enlarge and become oval or elongated.

• Mouseear Chickweed

  Mouseear chickweed is a low-growing perennial that can tolerate extremely low mowing heights (even at greens height). It can tolerate a wide variety of soil and growing conditions. The leaves of mouseear chickweed are typically very thick, dark green and covered with hairs.

• Wild Strawberry

  Wild strawberry is a trifoliate (three leaflets) weed that spreads by aggressive stolons. The leaves and fruit of wild strawberry are smaller than that of its cultivated cousin. Wild strawberry is usually found in low maintenance areas and prefers well-drained soils.

• Gray Snow Mold

  This disease is important in northern regions of the United States, where snow cover remains on the ground for extended periods, usually 3 months or more.

• Microdochium Patch

  This is the most important disease in areas with extended periods of cool wet weather. Symptoms appear as reddish brown to copper-colored spots in the turf.

• Slime Mold

  Slime molds are non-pathogenic fungi that occasionally dwell on many different turfgrass species.

• Waitea Patch

  Waitea patch is an emerging problem on annual bluegrass in Michigan. Symptoms typically begin as thin yellow rings, ranging from a few inches to a 1 ft (10 cm to 0.3 m).

• Quackgrass

  Quackgrass is a common grassy weed of turfed areas. Quackgrass is a perennial and can often be spotted by its dull blue-green appearance. Because quackgrass spreads by rhizomes (underground stems) it responds very well to cultivation practices. It is common to have quackgrass contamination in unscreened topsoil. Each rhizome section has the ability to produce a new plant.

• Common Lambsquarters

  Like many other summer annual broadleaf weeds, common lambsquarters is generally considered an 'establishment weed.' Common lambsquarters needs cultivation (bare, loose soil) to establish.

• Pythium Blight

  Pythium first appears as circular reddish brown spots in the turf, ranging in diameter from 1 to 6 in. In the morning dew, infected leaf blades appear water soaked and dark and may feel slimy.

• Bacterial Wilt

  Bacterial wilt is characterized by tiny red-copper-colored spots first appearing about the size of a dime. As more plants die, spots become larger. Small, yellow leaf spots, streaked tan to dark brown spots, dark green, water soaked lesions, shriveled blue to dark green leaves, and yellow elongated leaves are all symptoms that have been associated with bacterial wilt.

• Powdery Mildew

  Turf affected by the disease have a grayish white cast, with initial symptoms appearing as white patches on the leaf blade.

• Brown Patch

  Brown patch appears as circular patches, ranging from a few inches to several feet in diameter.

• Common Mallow

  Common mallow most often establishes along culverts, fencelines and near foundations. Common mallow forms a clump whorled branches that do not root where they touch the ground.

• Necrotic Ring Spot

  The pathogen attacks root systems in the spring and fall, and in the summer, infected plants begin to wilt in patches.

• Dollar Spot

  Dollar spot is characterized by round, bleached-out or straw-colored spots, ranging from the size of a quarter to the size of a silver dollar. Spots appear as sunken areas in the turf, especially low mown turfgrass.

• Goosegrass

  Goosegrass is a warm season summer annual grassy weed that predominates in exposed, trafficked conditions.

• Prostrate Knotweed

  Prostrate knotweed is a supreme indicator weed. Knotweed is the earliest germinating of all the summer annual weeds. Due to its early germination timing, knotweed is able to claim resources and invade damaged areas before other desirable grasses begin to grow.

• Yarrow, Common

  Common yarrow is considered a desirable herbaceous perennial by many gardeners and is sold in its cultivated form at most greenhouses.