Brown Patch – Fescue’s Biggest Summer Challenge
Fescue lawns are currently looking great! Temperatures right now are great for cool season turf, and we have had an abundance of rainfall, approximately 10” since the first of May.
Fescue lawns looking great…and rain. Could this be a problem?
It very well could be a problem because we have perfect conditions for fescue’s biggest summer challenge, Brown Patch.
The common belief is that fescue’s biggest summer challenge is surviving the heat.
But, in fact, fescue’s biggest summer challenge is surviving Brown Patch.
If don’t have any fescue in your lawn and are about to click delete… DON’T DO IT! There is valuable information at the end of this article about BAGWORMS.
There is a belief that fescue lawns require a lot of water to survive the summertime. But, the truth is too much water, either from rainfall or from overwatering, bad watering practices, is the reason Brown Patch is the biggest problem for fescue during the summer.
What is Brown Patch and why is it fescue’s biggest problem?
Brown Patch is the most common disease of fescue in Oklahoma. The pathogen (Rhizoctonia solani) that causes Brown Patch prefers warm temperatures and requires excessive moisture.
Brown Patch will develop anytime daytime temperatures are in the 90’s, nighttime temperatures stay in the 70’s and the turf leaf blades stay wet for 5 hours or more. Rain, or even just high humidities and excessive dew can be enough to keep your turfgrass wet for an extended period giving Brown Patch the opportunity to develop.
During June, typically Oklahoma City’s second wettest month, Brown Patch often occurs because the conditions for the disease are exactly right.
In July and August, as the climate moves from being more humid to being more arid, we should see less Brown Patch pressure on fescue lawns, but we don’t. As the summer gets warmer, we typically see more of the disease because the default tendency is to overwater fescue, and/or to water incorrectly.
Brown Patch appears as irregularly shaped larger areas of thinning, brown to yellow grass blades. Close inspection of leaf blades will reveal small, irregular, tan leaf spots with dark-brown borders.
Brown Patch will be more severe in areas of poor soil drainage, areas with poor air movement, areas with dense shade, and fescue that is over fertilized in the summer.
Fescue lawns that are watered daily, or watered in the evening, are likely to struggle with Brown Patch.
Brown patch
Do not use high rates of nitrogen fertilizer on fescue when temperatures are prime for Brown Patch during the summer months. Apply no more than ½ lb. of nitrogen per 1,000 square feet on fescue during summer months. The disease readily attacks the lush growth of grass promoted by nitrogen. During the early summer, fertilize fescue with a low nitrogen fertilizer containing higher amounts of phosphorus and potassium to strengthen the root system then do not fertilize again until temperatures begin to cool in September.
Keep the lawn mowed regularly at the proper height. Fescue should be mowed at 3 to 3 ½” in the summer. Lower mowing will increase disease severity. Remove clippings if you have an active outbreak of Brown Patch. Diseased clippings will feed the spread of the pathogen.
Do all you can to provide good drainage. Annual aeration in the fall will improve soil structure and improve water movement off the surface and into the root zone.
Close inspection of leaf blades will reveal small, irregular, tan leaf spots with dark-brown borders.
Brown patch disease loves mornings when there is a heavy dew.
Brown patch disease in fescue appears as irregular areas that lead you to believe the lawn may not be getting enough water.
What can be done to minimize the problem of Brown Patch on Fescue?
Selecting tall fescue varieties with a high resistance to Brown Patch is a critical first step. We recommend using a fescue blend with at least three varieties. Additionally, look for a mixture specifically for our area. The mixture we use to overseed fescue in the fall includes varieties that show high resistance to brown patch.
Avoiding prolonged periods of leaf wetness will drastically reduce the severity of Brown Patch. When temperatures are warm and fescue grass blades are wet for more than 5 hours at a time, the disease will be present. Do not water daily. Do not water in the evening. Water only when needed and only in the early morning. Deep soaking every other day is best practice. The goal is to get 1 ½” of water on fescue during the summer per week by watering no more than 3 times per week. Deep soak in the morning. Skip a day, then deep soak again.
Want to water your fescue less and still have a healthy fescue lawn? Contact us about our Water Retention Program.
Brown patch
A close look at the leaf blades in this area of fescue that is turning slightly brown and thinning reveals the presence of brown patch disease.
Watch this video to see the difference between brown patch and lack of water on a fescue lawn.
A key to managing Brown Patch in fescue is to water deep early in the morning every other day during the summer and avoid keeping the lawn moist for 5 or more hours at a time.
Overseed fescue in the fall. Avoid spring seeding of fescue. Brown Patch is more aggressive on young fescue while mature fescue is more resistant. It is common for spring seeded fescue to struggle with brown patch during the summer.
Have your soil tested every couple of years. Brown Patch will be more severe when the soil is not healthy, pH is too high or too low, or nutrients are out of balance.
The best way to prevent Brown Patch is to eliminate areas where the disease will thrive. Consider making changes to the landscape in areas with poor air circulation and dense shade. Small turf areas surrounded by structures, fences, and heavy landscaping are brown patch prone. You may find removing the turf and extending the landscape or planting groundcovers a better option.
Most importantly…. when we receive rainfall during summer months, turn your irrigation off for a few days. Allow time for your lawn and landscape to dry out, good for all types of turf, but critical for fescue.
Cultural practices are very important and the best practices for Brown Patch management.
Fungicides are effective for Brown Patch as either a preventive or curative treatment. Fungicides can be applied in late spring and early summer when the conditions are right for the development of the disease.
If your fescue is not looking its best, don’t assume it needs more water. Brown Patch will lead you to believe the lawn is too dry. Before you start watering, inspect the leaf blades for evidence of the disease and check the soil to see if it is dry.
Areas of dense shade and poor air circulation may be better served with ground covers such as liriope.
It is common for us to receive a call reporting:
“I just can’t get enough water on my fescue to keep it alive…” only to make a site visit to find a thinning fescue lawn struggling with self-induced brown patch from overwatering.
Bagworm Alert!
Bagworms start out very small, so small you may think they are just another needle or leaf.
Bagworms started showing up this week. Right now they are so small that unless you are looking for them you won’t see them.
Bagworms, very small bagworms, are starting to feed on your plants!
Bagworm Info:
Early in the life cycle the worm inside the bag is very small, about the size of a pencil lead. Treatment with an insecticide now will be very effective.
Do you notice the slight color difference between the two junipers? The one on the left is covered with hundreds of very small, almost unnoticeable bagworms that are quickly destroying the mature Taylor Juniper.
Bagworms, very small bagworms, are starting to feed on your plants!
Bagworm Info:
¼”-2” long spindle shaped bag wrapped in the foliage of the host plant. Young bagworms are very hard to spot.
Favorite host plants are juniper, arborvitae, spruce, pine, and cedar. But they can attach themselves to any deciduous shrubs and trees.
Females lay eggs in bags left on plants over the winter. One female bagworm will lay as many as 500 eggs. The eggs hatch in the late spring and tiny larva crawls out and start feeding. As they feed, they use silk and plant materials to protect and camouflage themselves. Bagworms can strip a plant of foliage. They are active from late May through September.
Heavy infestations, particularly on the same plant year after year, can cause plant death.
When there are only a few, control is best by hand picking. If you have a large population an insecticide treatment should be made as soon as they are noticed. Try to remove any bags left on plant material in the fall. Bags left on the plant will serve as cocoons for females to lay more eggs. When removing bags, destroy them. Do not pick and toss on the ground as the worm will crawl back to a plant.
Do your landscape a favor this weekend…inspect plants for very tiny bagworms. Your landscape will thank you with healthy shrubs full of rich color and texture.
Anytime you have questions or concerns about your lawn or landscape, give us a call. Our goal is to help you have your best lawn and landscape!
Lorne Hall
Hall | Stewart Lawn + Landscape
(405)367-3873
