A Tale of Two Brown Spots
by Ben Champlain - June 2006
If you are concerned about brown areas in your lawn, contact Ben Champlain, turf manager with Ryan Lawn & Tree, at (816) 246-1707.Homeowners know the joy and disappointment of lawn care, and brown spots in the yard are one of their most frequent frustrations. Brown spots can have very different causes, including drought, thatch, dog urine, and many more. Today’s tale involves Mary and Emma, two proud homeowners in Kansas City with very different and common causes for their brown spots.
Mary lives in a lovely neighborhood and has a thick, dark green fescue/bluegrass mixed lawn. She waters two to three times a week and mows every week at three inches. The morning of June 7 has arrived along with large, discolored areas throughout the lawn. She assumes that the brown spots are due to the heat and lack of rainfall, so she waters every day to help relieve the stress. However, by the end of the week the spots become larger and appear to have died.
Mary’s large, brown spots are due to a fungus called “Brown Patch.” The fungus presents as large, irregular brownish shapes throughout the yard. Further investigation reveals Mary was watering her lawn in the evenings, creating a moist and humid environment. The humid conditions, combined with nighttime temperatures above 65 degrees, contributed to the flare up of the fungus.
It is important to note that fungi can attack in many temperatures, but each requires specific conditions for it to flourish. “Pythium Blight” is a fungus that may appear under conditions similar to Brown Patch. Knowing conditions that contribute to brown spots and the variety of grass in your lawn is important in getting to the root of fungus problems. Let’s explore another example:
Emma is Mary’s neighbor. She knows what happened to Mary’s lawn and has taken the necessary steps to ensure she will not have a similar outbreak. August 20 is here and it is hot and dry. Emma is watering every morning, but she, too, has developed large, brown areas.
Emma’s large, irregular brown spots are likely due to grubs. The spots look exactly as Mary's did early in the summer. However, the grasses in Emma’s brown areas are rolling up like a rug, revealing 20 grubs per square foot. The larvae have eaten through the root system of the grass plants.
Solutions are available for both problems. Proper watering in the morning will reduce the fungus problem in Mary's lawn. A rule of thumb is to water before noon from May 15 to September 15 to allow grass blades to dry out before evening. In addition, there are fungicides that can be applied preventively and/or curatively to control Brown Patch outbreaks.
There are certain grub controls for Emma's problem that are very specific to grub larvae and provide little risk to the environment. Moreover, these products provide season-long control as preventative materials.
Even though Mary and Emma both had similar large, brown spots, they each had different problems. Knowing the time of year, the weather conditions and life cycles of pests can help determine the course of action needed when brown areas appear in lawns.