How to Recognize Turfgrass Weeds and Diseases

As the temperatures rise, so do turfgrass weeds and diseases. We’ll discuss the top turfgrass weeds and diseases our lawn care experts may see popping up on properties throughout San Diego County.

Turfgrass Weeds to Look For

Large Crabgrass

Large crabgrass seeds will germinate when soil temperatures reach 55 degrees Fahrenheit. These summer annual weeds lie flat along the ground via long, creeping, horizontal stems (stolons). They are easily identified by their large hairs, which protrude 90 degrees to the leaf or stem surface. Large crabgrass will also have larger and smoother leaf blades than most turfgrass.

 

 

Clover

Clover is a group of weeds characterized by a trifoliate leaf with three leaflets. Clovers are generally perennial plants that regrow from underground structures. Here are the types of clover species:

• White clover: Characterized by egg-shaped leaflets with a grayish watermark at the base.
• Black medic: Characterized by egg-shaped leaflets with an extended petiole (a stalk that attaches a leaf to a stem) on the middle leaflet.
• Burclover: Is like black medic but is tooth/serrated on the leaf margins and has hooked tips on the flower.

 

Nutsedge

These grass-like weeds are characterized by triangular stems with prominent edges. The most common Nutsedges are yellow nutsedge, purple nutsedge, and green kyllinga. These perennial weeds can regrow from underground structures, such as rhizomes or tubers.

• Yellow nutsedge: Can be identified by its yellowish seed head.
• Purple nutsedge: Has a purple to maroon seed head with tiny hairs.
• Green kyllinga: Smaller than the other two nutsedges and grows in dense mats with a terminal globelike seed and three long triangular leaves.

 

Poa annua and Poa trivialis

Poa weed species produce a lot of seeds. They also tend to be very diverse biologically. The seeds can germinate at many different times of the year, and depending on the climate, many can survive summers and winters and even behave like perennial plants.

 

 

 

Common Turfgrass Diseases

Dollar Spot

Caused by the fungus, Clarireedia jacksonii, this disease manifests as small, circular patches that look like light tan or bleached silver dollars. They may grow upward of 6-inches in diameter. If not managed correctly, the patches can merge and form larger areas of damage, which can lead to thin and weak turf.

 

 

Brown Patch

Caused by the fungus, Rhizoctonia solani, this disease is characterized by circular patches of brown or tan dead grass surrounded by a dark ring of active infection, ranging from 6 inches to several feet in diameter. It thrives in warm, humid conditions and can spread rapidly in some turfgrass species. Brown patch is more severe when nighttime temperatures are consistently above 70 degrees Fahrenheit.

 

Gray Leaf Spot

Caused by the fungus Pyricularia grisea, this disease typically affects newly established strands of grasses, like perennial ryegrass and tall fescue. It appears as small, tan lesions with dark brown borders and gray centers on leaf blades. During high moisture and humidity, the lesions will appear gray and fuzzy from fungal sporulation.

 

 

Rust

Turfgrass rust makes grass look yellow or orange when viewed from a distance. This fungal disease produces orange spores that can be transferred from leaf blades to shoes, pant legs, or mowers. Rust is a disease of slow-growing turf; newly seeded stands can be susceptible to rust infection.

 

 

Fairy Ring

Fairy ring is a circular area of abnormal turf growth. It is common in lawns with high levels of organic matter in the soil or where trees were recently removed. This isn’t a disease that attacks turf grass directly; it breaks down organic matter in the soil, such as old roots or tree stumps. As the organic matter breaks down, nitrogen is released, which results in dark green arcs or rings of thick, fast-growing grass. In some instances, the circles appear as brown or dead grass.

 

Experience Quality Service. The Difference…Is Growing

From weed abatement to fertilization, when it comes to maintaining lawns, no one does it better than Westturf Landscape Management. We take pride in providing landscape management services to keep your properties attractive and profitable. Call us 760-650-3120 or send us a message.