Plan the perfect garden with our interactive tool →

My Grass Has White Spots

...
Thinkstock/Comstock/Getty Images

Grass blades exhibiting white spots indicate a fungal disease called powdery mildew. Powdery mildew is the most widespread disease that infects plants, according to Colorado State University. However, gardeners can have peace of mind knowing that the fungal spores that cause lawn powdery mildew will not infect your other plants.

Powdery Mildew

Powdery mildew typically infects lawns during July through September, according to the University of Rhode Island. Fungal spores quickly germinate in a few hours when temperatures are cool and lawn is moist. Furthermore, powdery mildew fungal spores are almost always present in the lawns, but may not be infecting grass. Spores overwinter in dead grass debris and spread when the weather favors the disease. Because the disease can infect grass in two hours, gardeners can see severe powdery mildew symptoms in a week, reports the University of Rhode Island.

  • Grass blades exhibiting white spots indicate a fungal disease called powdery mildew.
  • Furthermore, powdery mildew fungal spores are almost always present in the lawns, but may not be infecting grass.

Identification

Upon close examination, gardeners can see tiny white spots on their grass. Spots may appear to look like powder. This powder is a combination of mycelium and fungal spores. Mycelium is the branching parts of the fungal spores. The disease sucks up the nutrients from the surface of the grass blades. Grass blades become malnourished and turn yellow from the result of the lack of nutrients. Also, severe powdery mildew infections cause small to large areas of the lawn to die out.

  • Upon close examination, gardeners can see tiny white spots on their grass.
  • Also, severe powdery mildew infections cause small to large areas of the lawn to die out.

Treating Powdery Mildew in the Shade

Grass growing in the shade is the most susceptible to contracting powdery mildew. Shady environments favor the germination and spread of powdery mildew fungal spores. Gardeners can control powdery mildew by cutting back overhanging branches in these areas. Trees that cast too much shade can be removed. Also, planting grass that tolerates shade will reduce the chances of powdery mildew damaging the lawn. Healthy grass tolerates moderate infections of powdery mildew. Shade tolerant grass types include St. Augustine, zoysia, fescues and supina bluegrass.

  • Grass growing in the shade is the most susceptible to contracting powdery mildew.

Cultural Management Strategies

Avoid overfertilizing your lawn to prevent stressing out the grass. Stressed out grass dies out when infected with powdery mildew. Avoid using more than 1 lb. of slow release fertilizer per 1,000 square feet at one time. Using too much nitrogen can burn grass and weaken grass blades. Furthermore, reduce your irrigation if you give your lawn more than 1 inch of water a week. Typically, lawns only need more than one inch of water each week to keep them from drying out.

  • Avoid overfertilizing your lawn to prevent stressing out the grass.

Related Articles

How to Take Care of Carpet Grass
How to Take Care of Carpet Grass
Grass Root Rot
Grass Root Rot
How to Improve Bermuda Grass Growth
How to Improve Bermuda Grass Growth
What Natural Home Remedy Will Kill Grass Fungus?
What Natural Home Remedy Will Kill Grass Fungus?
After Fertilizing Your Lawn, When Is it Safe to Let Your Pets on the Lawn
After Fertilizing Your Lawn, When Is it Safe to Let...
Will Household Bleach Kill Grass?
Will Household Bleach Kill Grass?
How to Kill Nutgrass in Bermuda
How to Kill Nutgrass in Bermuda
How to Kill Water Grass
How to Kill Water Grass
Garden Guides
×