I remember going into a neighborhood to diagnose a lawn problem in Crestview during spring a number of years ago. The centipedegrass lawn was in a state of decline. This was the front yard of the original model home for the neighborhood. The original owner sold the house and moved. The new owner, not familiar with North Florida lawns, was dissatisfied with the condition of his front yard.
All of the residents in this neighborhood were new to Florida.
At the time of my visit, the neighborhood was approximately ten-years-old. The original owner of the home was new to Florida, as well. He had only lived in the home for about two years before selling the house and moving to another state.
The original homeowner purchased the model home when the neighborhood was new and became the neighborhood lawn guru.
Imagine this situation… the entire neighborhood was new, everyone living in the neighborhood was new to Florida, not having a clue how to correctly maintain their new centipedegrass lawns.
Centipedegrass decline. Credit: Larry Williams
A sure way to kill a centipedegrass lawn is to be a little heavy handed with nitrogen. The natural color of a healthy centipedegrass lawn is light green, almost a crabapple green. The original homeowner was fertilizing his lawn as if it were a bermudagrass or fescuegrass lawn. Centipedegrass will not put up with this. As a result of “overdosing” his lawn with nitrogen, the lawn took on an unnatural dark green color. Short-term (two to three years), centipedegrass will appear to respond nicely to too much nitrogen. But after several years, irregular areas within a centipedegrass lawn will turn bright yellow in spring, followed by turning brown and dying back to bare ground as a result of too much nitrogen. The condition is called centipedegrass decline.
Healthy centipedegrass lawn with correct light green color. Credit: Dr. Bryan Unruh
I heard a minister ask the question, “Does the person you’re following know where he is going?” This was in reference to a parable found in the Bible in Matthew 15:14 where Jesus stated, “If the blind lead the blind, both will fall into a ditch.” This expression has many implications but basically is a caution about the dangers of following a leader who is clueless.
Unfortunately, this self-appointed lawn guru was clueless as to how to correctly manage a centipedegrass lawn. A few years following his overdoing it with fertilizer and then moving, his former lawn began to die in patches, progressively followed by other neighborhood lawns doing the same, almost like a domino effect. Who you choose to follow is important.
I don’t know if you’ve noticed, but it’s been hot outside. Like really, scorching, hellacious, dog days hot. In this weather pattern we’ve been in, it’s hard to make yourself do non-essential stuff outside that doesn’t involve swimming and so our gardens go by the wayside. In my opinion, that’s totally okay! Give yourself a rest from the garden and landscape chores for the next couple of weeks and get your fall gameplan ready. The following are some things to think about over the next few weeks to prepare yourself for the coming cooler weather!
Soil testing in centipedegrass. Photo courtesy of Daniel Leonard.
Get your soil tested. If you’re an in-ground vegetable gardener or just like to have an attractive lawn/landscape, performing a simple soil test can offer either peace of mind that your soil’s pH and fertility is good or give you a nudge to schedule some needed amendments. Though I don’t recommend fertilizing lawn grass this late and there’s no need to fertilize the garden before it gets planted in mid-late September, you can certainly begin to source and price fertilizer for the appropriate time based on your test results. However, now IS the perfect time to get lime out in a vegetable garden if your pH has sunk beneath the recommended 6.5. Lime takes weeks to months to begin to alter soil chemistry so the sooner the better if it is needed!
Order seeds. While I love to support local farm stores and plant nurseries, you are limited with the vegetable and flower varieties you can plant by what they have in stock. I enjoy trying new/improved and heirloom plant varieties each year and, most of the time, these can only be found by ordering online. For the latest in vegetable and cut flower varieties with a nice mix of heirloom cultivars thrown in also, I can recommend Johnny’s Selected Seeds, Baker Creek Heirloom Seeds, Seed Savers Exchange, and other similar purveyors – all of these are great places to look. Continue to purchase your more common standbys through local outlets but, this year get different and try new things by ordering online!
Develop a garden/landscape plan. I doubt there’s a gardener amongst us who wouldn’t like to rearrange things a bit outside. Maybe you planted your lettuce a little too closely together last year, you’ve been dreaming of installing a new flower bed, or you really want to do a full garden/landscape renovation. The best way to be successful at any of these things is to get outside (or at least look out from behind a window in the A/C), take stock of what is already there, the space that is or might be available, research what plants or varieties might do well in your yard/garden (your local UF/IFAS Extension office is a great resource for this), and begin to sketch your ideas out. This planning step WILL save you time and money by ensuring you don’t purchase too many plants, by picking plants that will do well, and ensuring you install everything at the correct time.
So, take advantage of the heat, stay inside, and work up your garden gameplan together this August – fall is just around the corner. For help with soil testing, recommendations on plant varieties to purchase, or working up a garden/landscape plan tailored to you, contact your local UF/IFAS County Extension Office. Stay cool and happy gardening!
A mole cricket has a face only a mother could love. They are so strange looking, in fact, that in the past week I’ve had two people ask me what they were. They have large, round, helmet-like heads, undersized eyes, and massive front claws used for digging. Unlike your garden-variety crickets, which really don’t cause any major damage to home landscapes, the mole cricket is quite the turfgrass menace. Instead of hopping about aboveground, they tunnel beneath the lawn and feast on the roots and leaves of grass, often destroying entire yards. They are also vegetable pests, going after tomatoes, cabbage, and peppers.
A young mole cricket. Its round head and large front claws distinguish it from other cricket species. Photo credit: Lucy Adams StevensonA) Horizontal and B) vertical view of a generalized tawny mole cricket burrow showing 1) horn, 2) 1st constriction, 3) bulb, 4) 2nd constriction, 5) turn-around, 6) surface tunnel, and 7) deep tunnel. Figure 1 from Nickerson et al. 1979. Ann. Entomol. Soc. Am. 72(3):438-440.
Mole crickets spend most of their time below ground and form burrows for hiding, laying eggs, and traversing through their territory. In mating season, males create a monotone song that averages 88 decibels—as loud as a motorcycle! The call comes from their burrows, which have funnel-like openings that expand at the surface, creating amplification comparable to a horn.
Beneficial larra wasp parasitizing a tawny mole cricket. Photo credit: UF IFAS
The tawny mole cricket (Neoscapteriscus vicinus) is the most common to our area and is an invasive species from South America. UF IFAS has had a specific research program related to mole cricket management since the late 1970’s. One successful outcome of this program has been the introduction of a biological control species, the larra wasp (Larra bicolor). The wasp manages mole cricket populations by stinging and temporarily paralyzing crickets. A female will then deposit an egg into the mole cricket’s body. The cricket recovers and goes about its daily routine until the egg hatches, at which point the larval wasp feeds on and eventually kills the mole cricket. Along with the wasp and release of flies and a nematode that also manage mole crickets, the biocontrol methods introduced between the 1980’s and 2004 have resulted in a 95% reduction in mole cricket populations in north Florida.
If you are seeing mole crickets, you can attract larra wasps to your property by planting shrubby false buttonweed or partridge pea plants, which the wasps feed on. If you have serious damage from mole crickets, check out this thorough Mole Cricket Integrated Pest Management Guide, or contact the horticulture agent at your local county extension office to get a site-specific recommendation for management.
Centipedegrass is a low maintenance turfgrass for North Florida landscapes. Scientists from Georgia also found an added benefit when the grass is in flower. Learn about the specific insects found visiting the flowers of centipedegrass.
It amazes me that even under flood conditions, people still water their lawns.
I’m sure you’ve seen it too – we get enough rain to cause some areas to flood and yet you see irrigation systems going full blast.
Lawn irrigation should be applied on an as needed basis. Credit: Larry Williams
We should water our lawns, landscapes and gardens on an as-needed basis. The way that some people water their lawns is as logical as saying that a pet dog needs a drink of water at 4 p.m. everyday. This is not true. When watering, we are simply replacing water that is lost. This is true when we drink water ourselves, when we provide water for a pet dog, or when we provide water for our lawns, landscapes and gardens.
An irrigation system is a great tool when used to supplement rainfall. Irrigating too much not only wastes water but it also is the cause for many lawn problems such as shallow, weak root systems, leaching of fertilizer and numerous lawn diseases. Cutting the irrigation timer to off and operating the system manually will solve many lawn problems.
Also, there are tools to prevent an irrigation system from coming on during rain or when adequate rainfall has occurred. As a matter of fact, it has been state law in Florida for every automatic irrigation system to have a rain shutoff device installed since 1991.
Florida Statutes, Chapter 373.62 – Water conservation; automatic sprinkler systems states, “Any person who purchases and installs an automatic lawn sprinkler system after May 1, 1991, shall install a rain sensor device or switch which will override the irrigation cycle of the sprinkler system when adequate rainfall has occurred,”
Rain sensors are available, inexpensive and are not difficult to install. Rain shutoff devices really do work when installed properly. If you do not feel qualified to install such a devise on an existing system, check with a reputable irrigation company.
Water only when lawn indicates that water is needed. When the grass needs water, leaf blades fold along the midrib – like a book closing, footprints remain in the lawn long after being made and the lawn turns grayish in spots, indicating it needs water.
When 30 to 40 percent of the lawn shows these signs of water need, turn the irrigation system on and let it run long enough to apply one-half to three-quarters inch of water. Don’t water again until the lawn begins to show these signs of water need. Watering this way will develop a deep-rooted lawn and landscape. Here’s a UF/IFAS Extension link with more information on lawn and landscape irrigation. https://gardeningsolutions.ifas.ufl.edu/care/irrigation
Does your yard have patches of dead grass or areas that look thin and weak? The last two summers of heavy rain and the stress of December’s freezing weather have contributed to widespread outbreaks of Take-All Root Rot, a soil-inhabiting fungus Gaeumannomyces graminis var. graminis that causes yellow grass patches ranging in diameter from a few inches to more than 15 feet. The symptoms first appear in the spring, but 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. Because 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; potentially years. If the turfgrass is not stressed, leaf symptoms may never be observed. To confirm the presence of TARR, submit a sample to the UF Pathology Lab.
This disease is very difficult to control once the above-ground symptoms are observed. Measures that prevent or alleviate stress are the best methods for controlling the disease. Any stress (environmental or man-made) 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 issues. 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.
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. 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.
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 its 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 tires 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 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. But, 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.
Now that we have added another major stress with the recent heavy rain, it will be very important to continue monitoring the turf and being cautious about the cultural practices being used. Take-All Root Rot is likely to flourish. Do not encourage its development.
If the damaged areas are small, it may be possible to encourage turfgrass runners to grow back into the space. Application of 50/50 blends of sphagnum moss and course white sand can be used to top-dress the damage areas. Add no more than 1-inch of the mixture per application. After the stolons have crept into the voids and received a mowing, more top-dressing can be applied. Repeat until the grass stops growing in the fall. Fungicides applied in the spring and fall will help to keep the Gaeumannomyces graminis var. graminis suppressed.
