Still fighting Brown Patch or Large Patch lawn diseases? You’re not alone

I’ve been reading lately, seasonally appropriate diversions on summertime lawn and garden subjects, about obsessive compulsive lawn owners checking individual blades of grass many times a day, some even creeping out in the nighttime temperatures, looking with flashlights to see if their blades of grass are standing up properly, not weighed over with too much moisture or heaven forbid, a child or family member having played too roughly or even just too long on the lawn.

So, while it adds humor to many of the unnerving real summertime lawn pests, it cannot blind our eyes to the brown patch and large patch diseases that are prone to make direct hits right now on our lawns as temperatures and humidity levels soar.

It doesn’t take long for a beautiful lawn to be destroyed by Brown Patch or Large Patch as these fungal infections spread rapidly. And mid-summer in Oklahoma our high humidity and near 100-degree days are the perfect environment for the fungus to make its move. Serious fungal diseases thrive in high temperatures, anywhere from 65 to 88 degrees, so when you consider our very hot days turn into very warm nights, Oklahoma lawns are hot for 10 to 12 hours even during the nighttime. Add to that humidity, over even 60 percent, allows for extended periods of wetness. Most often Brown Patch begins on cool season grasses like tall fescue lawns during late spring but can run thru July and kill an entire lawn if ignored and left untreated.

Both Brown Patch and Large Patch symptoms can vary greatly depending on the type of grass and soil conditions. Generally small spots of light brown grass begin to appear, that are a few inches to several feet in diameter. Often there’s a yellowish “smoke ring” around the perimeter of the patch. Often the center of the patch will recover, leaving a doughnut-shaped pattern.

Close inspection of cool season grass blades will show small, irregular, tan colored leaf spots with dark brown borders. Other grasses will appear as brown and shriveled leaves, rotted near the soil surface.

Conditions favorable to mold, discussed above, can uniformly thin and kill entire lawns.

The best way to prevent these fungal infections is to follow good lawn care practices. These include selecting an appropriate grass type for your home and climate. Well-chosen grass types are stronger and able to fight off mold spores native to our home environments. Avoiding high nitrogen rates on warm season grasses in mid to late fall. New growth is more susceptible to the fungus.

Consider going organic as overuse of pesticides and fungicides can upset natural environmental strengths.

Watering schedules need to be sufficient to sustain the turfgrass through dry summer conditions, but most extension service and lawn professionals will recommend watering in the early morning instead of the evening where wetness can linger.

If certain areas of your lawn are more prone to the problem, consider naturalizing the area with ground covers or flowerbeds more suited to the conditions.

Be sure lawns are mowed to their proper heights based on the species of lawn you own and be sure there is good drainage to allow runoff of excess water.

Soil testing is also very helpful as disease may be more severe if the soil pH is less than 6.0. It may require lime application.

While fungicides cannot always be relied upon to rid a lawn of the diseases, regular application can improve the lawns appearance. Sometimes alternating fungicides is more effective in gaining control of the fungal diseases.