by Sheila Dunning | Sep 16, 2015
“We have replaced this grass several times over the past few years; and it’s dying again.” I have heard this complaint too many times this summer. Last summer’s heavy rain, the stress of January’s icy weather, and this year’s extended summer have contributed to widespread outbreaks of Take-All Root Rot, a soil-inhabiting fungus Gaeumannomyces graminis var. graminis.
Symptoms of Take-All-Root-Rot. Photo credit: Sheila Dunning, UF/IFAS.
This disease causes yellow grass patches ranging in diameter from a few inches to more than 15 feet. The symptoms first appear in the spring, but the disease can persist all summer and survive the winter. Over time, the entire area dies as the root system rots away. The pathogen is naturally present on warm-season turfgrass roots. High rainfall and stressed turfgrass trigger the disease.
Since the roots are affected, they are not able to efficiently obtain water or nutrients from the soil, nor are they able to store the products of photosynthesis, which result in the loss of color in the leaves. By the time the leaf symptoms appear, the pathogen has been active on the roots for several weeks, probably longer; the disease has been there potentially for years. If the turfgrass is not stressed, leaf symptoms may never be observed.
This disease is very difficult to control once the aboveground symptoms are observed. Measures that prevent or alleviate stress are the best methods for controlling the disease. Any stress (environmental or manmade) placed on the turf weakens it, making it more susceptible to disease. Remember, that every maintenance practice, fertilizer application, and chemical (especially herbicide), application has an impact on turfgrass health. Cultural practices that impact the level of stress experienced by a lawn include:
- proper turfgrass species selection
- mowing at the correct height
- irrigation timing, frequency and volume
- fertilizer: nitrogen and potassium sources and application quantities
- thatch accumulation, and
- soil compaction
The selection of turfgrass species should be based on existing soil pH, sunlight exposure, use of the area and planned maintenance level.
Mower blades must be sharp to avoid tearing of the leaves. Additionally, turfgrasses that are cut below their optimum height become stressed and more susceptible to diseases, especially root rots. When any disease occurs, raise the cutting height. Scalping the grass damages the growing point. Raising the cutting height increases the green plant tissue available for photosynthesis, resulting in more energy for turfgrass growth and subsequent recovery from disease.
If an area of the lawn has an active fungus, washing or blowing off the mower following use will reduce the spread of the disease to unaffected areas.
The amount of water and the timing of its application can prevent or contribute to disease development. Most fungal pathogens that cause leaf diseases require free water (rainfall, irrigation, dew) on the leaf to initiate the infection process. Irrigating every day for a few minutes is not beneficial for the turfgrass because it does not provide enough water to the root zone, but it is beneficial for turfgrass pathogens. It is always best to irrigate when dew is already present, usually between 2 and 8 a.m., and then only apply enough water to wet the root zone of the turfgrass.
Excessively high nitrogen fertility contributes to turfgrass diseases. The minimum amount required for the grass species should be applied. Potassium (K) is an important component in the prevention of diseases, because it prevents plant stress. Application of equal amounts of nitrogen and potassium is recommended for turfgrass health. When turfgrass roots are damaged from disease, it is beneficial to apply nutrients in a liquid solution. However, nitrate-nitrogen increases the severity of diseases, so their use should be avoided when possible. Ammonium-containing fertilizers are the preferred nitrogen sources.
Heavy liming has also been linked to increases in Take-All Root Rot. Since most turfgrasses can tolerate a range of pH, maintaining soil at 5.5 to 6.0 can suppress the development of the pathogen. When the disease is active, frequent foliar applications of small amounts of nutrients is necessary to keep the turfgrass from declining.
Additional maintenance practices that need to be addressed are thatch removal and reduction of soil compaction. Excessive thatch often causes the mower to sink which can result in scalping and reducing the amount of leaf tissue capable of photosynthesizing. Thatch and compacted soil prevent proper drainage, resulting in areas remaining excessively wet, depriving root systems of oxygen. Since recovery of Take-All-Root-Rot damaged turfgrass is often poor, complete renovation of the lawn may be necessary. Removal of all diseased tissue is advised.
As a native soil-inhabiting pathogen, Take-All-Root-Rot cannot be eliminated. However, suppression of the organism through physical removal followed by proper cultivation of the new sod is critical to the establishment of a new lawn. Turfgrass management practices, not chemicals, offer the best control of the disease.
It is acceptable to use fungicides on a preventative basis while rooting in the sod. Azoxystrobin, fenarimol, myclobutanil, propiconazole, pyraclostrobin, thiophate methyl, and triadimefon are all fungicides that can be utilized to prevent disease development while having to excessively irrigate newly laid sod. Ideally, the turf area should be mowed and irrigated prior to a fungicide application. Unless the product needs to be watered in, do not irrigate for at least 24 hours after a chemical treatment. Do not mow for at least 24 hours, to avoid removal of the product attached to the leaf blades.
With all the stresses that our lawns have experienced, it is very important to continue monitoring the turf and be cautious about the cultural practices being used. Take-All Root Rot is likely to flourish. Do not encourage its development. A pathology test with the University of Florida Laboratory can confirm the presence of the disease causing organism. Before resodding again, have the dying sod tested.
For information and the submission form go to:
Sample Submission Guide
For more information on the disease go to:
Take-All-Root-Rot
by Carrie Stevenson | Mar 17, 2015
A waterfront buffer zone may include a raised berm with native vegetation to slow runoff from a yard before entering the water. Photo credit: Carrie Stevenson
A taste of spring weather has arrived, and people will soon be filling the home improvement stores and getting ready for outdoor projects. If you live on the water or near a storm drain, it’s worth considering buffer zones and best management practices for fertilizing and lawn maintenance.
A waterfront buffer zone is an area the length of one’s property line, typically running about 10 feet (although it can be wider) from the edge of a shoreline (or even a storm drain) into the yard. In this area, the homeowner allows native vegetation to grow along the water and uses low-maintenance plants within the buffer. In this zone, no fertilizers or pesticides are used. Some homeowners will build a small berm to divide the area of maintained lawn (uphill) from the downhill waterfront side. This berm may be composed of a mulched area with shrubbery to catch and filter runoff from the more highly maintained lawn. This combination of actions helps treat potentially polluted stormwater runoff before it reaches the water, and keeps homeowners from using chemicals close to the water. It is often quite difficult to grow turf next to the water, anyway, and this takes the pressure off of someone trying to grow the perfect lawn down to the water’s edge. The buffer zones are often quite attractive and can be an excellent transition between managed turf and the waterfront.
Unmaintained dirt roads along creeks are significant sources of sediment, which can harm the bottom-dwelling insects that form the base of the food web. Photo credit: Carrie Stevenson
Erosion prevention is crucial along waterways, as well. An open, non-vegetated lot can contribute a significant amount of sediment to a storm drain, stormwater pond, or natural body of water. Whether grass, trees, or bushes, any kind of vegetation is preferable to soil washing out of a yard and into the water. Sediment is a problem because it causes water clarity to drop, which can prevent seagrasses from getting the sunlight they need. Once settled, underwater sediment can form a stifling layer that chokes out small insects and invertebrates, which live in the soil and form the basis of the aquatic food chain. With no fish food available, fish may die or move out of an area. The most dramatic examples of this can often be found at dirt roads that cross over creeks. If not managed properly, the clay on these roads can nearly bury a small stream.
Other lawn care techniques for protecting the waterfront and preventing stormwater pollution include not mowing along the water, using a deflector shield and staying 3’-10’ away from the water’s edge when fertilizing, and not allowing grass clippings to blow into storm drains. Large amounts of decaying grass in a waterway can use up available oxygen, endangering aquatic organisms. When applying granular fertilizer, be sure to sweep up any spills on concrete so it doesn’t run into a storm drain. When cutting grass, mow at the highest height recommended for your turf to encourage deep rooting and stress tolerance. Healthy turf is better able to withstand drought, pests, and choke out weeds, reducing the frequency of pesticide and water application.
by Roy Carter | Jun 23, 2014
Summertime is vacation time for people, not plants! While getting ready for that long awaited trip, it’s easy to forget about your lawn, landscape, vegetable garden and house plants. A little time spent preparing your leafy friends for your absence could save you needless worry and hours of extra work when you get back.
Prepare your landscape for your absence.
Photo by Mary Derrick, UF IFAS
A vacation may be relaxing and rejuvenating for you and your family, but it can be hazardous, even deadly, for your plants. Unless you make adequate preparations before leaving, you could return to vegetable disaster.
One of the first things you might do before leaving home is ask a neighbor to check your plants periodically while you’re gone. All plants need some care. During an extended vacation container grown plants require special attention and different species have different needs. Be sure you give your friend specific instructions for the care of each type.
If you can’t find someone to personally look after your plants while you’re away, there’s plenty you can do prior to departure to make sure you don’t come home to a limp landscape and sickly house plants. Outdoor container plants should be placed in a shady area to conserve moisture. Under a tree or on the north side of a building are good locations. A thick layer of mulch will help conserve moisture for landscape plantings. Mow your lawn just before leaving, cutting the grass a little closer than usual. An unkept lawn can encourage disease, and it’s a tell-tale sign that no one’s home.
Give lawn and landscape plants a heavy watering – especially recently planted beds, which will need extra moisture. Also, thoroughly spray or dust your plants to protect them from insects and diseases while you’re away. If you have flowering annuals, cut the blossoms before departing. If you don’t, they’ll soon stop blooming. Harvest all ripe or nearly ripe fruits and vegetables. Like flowers, they will continue to produce only if they’re picked frequently. Otherwise, they’ll go to seed.
Do a thorough job of weeding. If weeds are allowed to go to seed while you’re away, you can expect to encounter much more difficult problems later in the season – even next year – when the seeds sprout. Weeding eliminates a major source of competition for your landscape plants’ food and water which may be in short supply during your absence.
Plants kept indoors require special consideration. Before leaving home, place your house plants in a room which receives indirect sunlight. Direct exposure to the sun will dry the soil too quickly. Of course, you don’t want to put your plants in a room that’s too dark, either. Too little light will almost always result in leaf drop. And, just before you depart, be sure to water your house plants thoroughly. This is especially vital, because – unlike lawn grass and landscape ornamentals – house plants cannot benefit from any rain that may fall while you’re gone.
You’ll enjoy your vacation more by making sure your plants are well prepared for your absence.
by Julie McConnell | Apr 21, 2014
Captiva St. Augustinegrass Credit: Julie McConnell, UF/IFAS
Mowing is an important and often overlooked landscape best management practices that can increase lawn health.
Most of us mowed lawns to earn some spending money as kids. As long as it was shorter when we finished than when we started our customers were happy. Although mowing seems like a simple chore that anyone can do, it turns out that improper mowing can cause a lot of damage to lawns and can increase pest and disease issues.
Make sure your lawn mower in good working order. Ensure the blades are sharp and the engine is not leaking any oil or gas products that may damage your lawn. Dull or damaged blades will give a ragged cut to grass blades that make it easier for disease and insects to attack your lawn. Leaking fuel products can damage or kill turf. Keep your mower clean by blowing or rinsing it after use, this simple step will also reduce the spread of weeds, insects, and disease.
Know the recommended mowing height for your type of turf (see table below) and follow it! Cutting turf below the recommended height places stress on the grass and encourages shallow roots. Deep roots help turf handle stresses such as drought, shade, insects, disease, or traffic. If any of these circumstances are occurring, the mowing height should be increased and fertilization should be decreased.
Mowing Height Table
| Turfgrass Type |
Recommended Mowing Height |
| Bahiagrass |
3.0-4.0 inches |
| Bermudagrass |
0.75-1.5 inches |
| Centipedegrass |
1.5-2.5 inches |
| St. Augustinegrass |
3.5-4.0 inches, Dwarf Cultivars 2.0-2.5 inches |
| Zoysiagrass |
1.5-2.5 inches, cultivar dependent |
When mowing, never remove more than 1/3 of the leaf blade per cutting. If the grass is overgrown, plan to mow in stages to avoid scalping or removing too much of the leaf blade. Just like shrubs, turf needs leaf surface area for photosynthesis. Allow clippings to fall onto lawns rather than catching them or discharging onto hard surfaces. The grass will decompose rapidly and provide nutrients to the lawn. Clippings that are blown onto sidewalks, streets, or other hard surfaces may be washed into storm drains and get into water systems. Just as decomposed clippings provide helpful nitrogen and phosphorus to our lawns, these same nutrients are harmful to our water bodies. Keeping them in lawns is a great way to recycle and to keep our water clean.
To learn more about caring for your turf click on the link below.
Bahiagrass for Florida Lawns
Bermudagrass for Florida Lawns
Centipedegrass for Florida Lawns
St. Augustinegrass for Florida Lawns
Zoysiagrass for Florida Lawns
by | Aug 19, 2013
As if mowing the lawn wasn’t trouble enough, dealing with and disposing of grass clippings is a major pain.
Clumps of grass clippings left on the lawn are unsightly and cause the grass beneath them to turn yellow due to a lack of sunlight as well as oxygen.
That problem is somewhat eliminated if you have a bag attachment on your mower, but handling the grass clippings extends the chore of mowing by taking extra time and effort to repeatedly empty the bag. Then, once clippings are put in garbage bags and placed on the curb, our municipal waste handlers must deal with them.
What to Do?
On the other hand, if we manage our lawns correctly and use proper cutting practices, we can have nice lawns without bagging clippings.
Properly managed, grass clippings will not contribute to thatch buildup or other problems. As they decompose, grass clippings also can supply much of the nutrients needed by your lawn.
Since you’ve already got it, why throw it away?
Bag-free Lawn Care Plan
You can follow this bag-free lawn care plan using a traditional lawn mower:
- For an established lawn, cut at the lower recommended cutting heights for your grass and use the lowest recommended amount of fertilizer. Mowing grass at a lower height will discourage thatch build-up.
- The rule of thumb for when to mow is to remove no more than about one-third of the leaf area at a time. If this practice is followed, the clippings will be small enough to sift into the turf and naturally decompose near the soil surface.
- To be successful, you will need to mow frequently enough so that the clippings are not too large. This may mean that the lawn can’t necessarily wait until Saturday morning. You must also mow at the recommended height. To ensure that your blade is set at the recommended height, set the mower wheel height on a concrete surface.
Here are some recommendations on various grasses and the heights at which to mow the grass:
- Common Bermuda: mow at approximately 1½ inches.
- Hybrid Bermuda: mow at approximately 1¼ inches.
- Zoysia: mow at approximately 2 inches.
- St. Augustine: mow at approximately 3 inches.
- Centipede: mow at approximately 2 inches.
Under the bag-free plan, you may apply a second application of fertilizer to your lawn this month (The first application should have been done in late April.). But remember that fertilizing grass increases its rate of growth. Reducing the amount of fertilizer you apply to the lawn will reduce the amount of clippings you will have to deal with. However, the one turf I would completely eliminate from a second fertilizer application annually is centipede. Too much fertilization in centipede can cause many more problems than any benefits that may arise from it.
A complete turf fertilizer is recommended for the average lawn. The best is a blend with more nitrogen, little phosphorus and some potash. Fertilizers with nitrogen, phosphorus and potassium ratios of 3:1:2 or 4:1:2 are good for turf. Choose a blend that contains some controlled-release nitrogen for longer feeding.
Don’t forget that recycled clippings also add nutrients, so fertilize at one-half the recommended rates – or not at all – if the grass color, growth and general appearance are acceptable.
Other practices will add to your success. First, don’t over water your lawn. During the hottest summer period lawns don’t need more than about an inch of water a week. Water as needed for weather conditions, and wait until the grass actually shows some stress before watering. Drought-stressed lawns often appear slightly faded, and the grass blades may be folded or rolled up.
Cut your grass when the leaf blades are dry (wait for the dew to dry). The clippings will sift down to the soil better. Make sure your mower blades are sharp, and keep the mower housing clean for best cutting and movement of clippings. You may need to have your mower blade sharpened once or twice in the growing season to properly cut your grass rather than having a dull blade ear your grass.
If you own or are thinking of buying a mulching mower, you’ll find they do an excellent job of chopping grass clippings and fit very well into this kind of program. Because these mowers are designed specially to chop grass clippings finely and return them to the lawn, they are a bit more forgiving if you wait slightly longer than recommended before mowing. Always avoid letting the grass get excessively tall before you mow.
For more in depth lawn care information, consult “Your Florida Lawn” or contact your County Extension Agent.
by Julie McConnell | Aug 5, 2013
Chamberbitter
Above average rainfall this summer has supplied water to more than just our landscapes, weeds are benefiting and flourishing as well.
Just as with any other landscape pest, proper weed control starts with accurate identification and knowledge about the life cycle of the weed.
When weeds are low in number, mechanical control (pulling, mowing) is a good start. If weed population continues to increase and herbicide options are considered, several questions need to be answered before product application.
Questions you need to ask yourself about your weed and site:
- What weed(s) are you trying to control?
o Be sure you know what the name of the weed is so that you can find it on your product label “weeds controlled” list; if you need help with identification contact your local county extension office
- What is your site?
o Lawn – specific turfgrass is important, what is safe to use on one type may kill another
o Ornamental beds – again note specific plants near your treatment area in case of sensitivity
o Water bodies – some herbicides are not labeled for use within a given distance of water; if the weed is in or around the water only use herbicides listed for aquatic weed control
- What is the life cycle of your weed?
o Annual – one season life cycle, summer annuals complete their life cycle between spring and fall; winter annuals are active between fall and spring
o Biennial – two growing season life cycle
o Perennial – plant lives for three or more years
- What category does your weed fall into?
o Grasses – one seed leaf as it emerges from the soil; hollow, rounded, stems with nodes, parallel veins in true leaves; examples are crabgrass, dallisgrass, cogongrass, torpedograss
o Broadleaves – have two seed leaves and true leaves have net-like veins and usually have showy flowers; examples are lespedeza, dollarweed, clover, chickweed, henbit, florida betony
o Sedges/Rushes – sedges have solid triangular stems; rushes have round stems; both like moist or wet habitat; examples are purple nutsedge, yellow nutsedge, beak rush
Dollarweed: Image Credit Edis ENH1128
Basic information about herbicide categories:
For more information read EDIS Publication “Weed Management in Home Lawns”
