With the changing temperatures, fickle weather, and rapid growth of spring and early summer, conditions are ideal for mold, fungus, and disease to take root in your lawn. Many of these issues are easier to treat the earlier you can spot them. Familiarize yourself with the signs of these common Minnesota lawn diseases, so you can address them before they run rampant on your turf.
Common in the cool-season grasses of Minnesota, leaf spot appears in spring, then again in fall. A close look at your grass might be necessary to identify the early stages of this leaf spot—it begins with brown-purple spots with tan centers along the individual blades of grass. The spots will eventually expand, taking over the whole leaf as the disease enters melting-out, the advanced stage. Melting-out can quickly kill large patches of grass, giving the appearance that your lawn is suffering from a lack of water.
Early treatment with fungicides is especially important when it comes to leaf spot. After the disease advances to melting-out, fungicides likely won’t do much to help your lawn.
Leaf spot thrives when dry heat alternates with wet, cool conditions. You can help prevent leaf spot by giving your lawn consistent waterings with respect to rainfall. However, don’t water during the evening—if the grass doesn’t have enough time to dry before temperatures drop, it can encourage leaf spot. In addition, make sure you’re not cutting your grass too short, and keep your thatch under the recommended ¾ inch, as it can trap in and harbor disease when too thick.
Dollar spot shows up from spring to summer, when the air is humid and the soil is dry. The disease begins with small patches of slightly sunken, straw-yellow grass, about the size of a silver dollar, but these patches will continue to expand to as large as six inches or more. If you take a closer look at the blades, you’ll see tan, dry-looking bands with red-brown edges running across the blade.
The bad news? Dollar spot is far easier to prevent than treat. In some cases, good fertilization and fungicide can help your lawn overcome and recover from dollar spot. If you spot it in your yard, bag your grass clippings to avoid spreading the dollar spot to other patches of grass.
As for prevention: don’t trim your lawn too short and don’t overwater, especially during the evening. Thorough, infrequent waterings are best when it comes to preventing most lawn diseases. Additionally, aerate your lawn in the spring to allow moisture to reach the grass roots.
Appearing during the spring-to-fall period, powdery mildew pops up in shady areas with poor circulation. Fairly easy to spot, this fungus presents as a white powder or film on the blades of grass—it should look like patches of your lawn have been sprinkled with baby powder.
Fungicides will control powdery mildew, but it will return if the source of the problem isn’t dealt with. As with dollar spot and leaf spot, adjust your watering schedule to allow the area to dry out fully before night falls. Consider pruning back the trees or shrubs around the affected area to improve the sunshine and air circulation.
Most Minnesota lawn diseases can be prevented with a good lawn care schedule. Stop in to Mimbach Fleet Supply to find the fungicides, grass seed, and fertilizer you need to help your yard thrive this spring.