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.
As the weather warms up, people will be outside tending to their landscapes more often. Part of that tending involves a simple thing that everyone knows plants need: water. And that is correct! Plants DO need water, and most of them need it regularly. However, even with the sandy soils in our area that drain quickly, it is possible to overwater your plants!
Overwatering can cause patchy dieback of shrubs and trees.
It is not uncommon to have a dry spell in the spring or fall in North Florida. Weeks may pass by with little or no rain, until the summer rains settle in. People may set their irrigation systems to deal with the lack of rain, but then forget to change the settings once the water isn’t needed. When plants receive too much water, we see a number of things happen. Trees and shrubs may appear to be deficient of nutrients, displaying yellowed leaves. They may die back and have a patchy appearance. Sprinklers that run constantly and splash water on leaves may increase the number of fungal diseases that plants get. Lawns that stay too damp may start seeing moisture-loving weeds such as dollarweed pop up in profusion. Luckily, we do have some guidelines for how much we should water.
For lawns or landscape plants, it is important to know what plants you are dealing with. Different plants have different needs when it comes to irrigation. Plants should be grouped by their water (and light) needs in a landscape, and irrigation zones should be set with those groupings in mind. Plants that enjoy or tolerate more water include wax myrtle, yaupon holly, swamp sunflower, swamp milkweed, pond cypress, and river birch. Others enjoy drier and well-drained soils, such as yucca, oleander, false rosemary, and turkey oak. To help determine the cultural needs of various plants, try consulting the Florida Friendly Landscaping Guide to Plant Selection and Landscape Design or the Florida Native Plant Society’s website.
When deciding whether or not to irrigate, one thing to pay attention to is the weather. All too often sprinkler systems will continue to run despite the weather – even in the middle of a thunderstorm! Install a rainfall shutoff device or make sure yours is functioning properly to avoid this. Overwatering can lead to unhealthy plants, disease issues, and weed problems.
Improperly placed or calibrated sprinklers can lead to lawn problems!
It can help to learn what a thirsty lawn looks like. Turfgrass that needs a drink will fold up its leaves, become dull bluish-green in color, and footprints will remain instead of the grass springing back. When signs of drought stress are evident, it’s time to water.
How much to water? The recommended amount is ½ to ¾ inch of water per application. Different irrigation emitters put out different amounts of water over time, so some measurement is necessary. Put out some small, straight-sided cans such as tuna or cat food cans in the area to be measured, run the irrigation for 15 minutes, and then measure how deep the water is in the cans. If you’ve collected ¼ inch of water in that time, you’ll know that you need to run the system for 30-45 minutes to give your lawn a thorough watering.
For more watering tips, there is plenty of information available. Check out these links:
Florida is rapidly urbanizing with 1,000 people a day moving into the state. Many cities in the panhandle have experienced accelerated growth rates over the past ten years. Crestview is one of the seven areas in the state with a population growth of 19% or greater, and the only one located in the panhandle. The 2030 predictions for Florida are another 6 million people, with counties containing military personnel increasing the quickest.
All of these people need water to meet their daily living needs. The average person in the United States uses 101.5 gallons of water per day. Residential water use comprises 61% of the public supply category. This category is responsible for the largest single portion (43%) of groundwater withdrawal in Florida. The Floridan aquifer spans an area of about 100,000 square miles in the southeastern United States, including all of Florida, as well as, portions of three other states. At the current statewide population growth rate, Florida is facing a 300 million gallon per day shortfall of future water needs, possibly as early as 2030.
Turfgrass is a key landscape component and often the most commonly used single type of plant in the residential landscape. However, on a hot, sunny day in midsummer, the average lawn uses 125 gallons of water per 1,000 square feet. Although Florida has a humid climate where the precipitation rate, on average, is greater than the evapotranspiration rate, the low water-holding capacity of the soil makes irrigation necessary for the high quality landscapes desired by homeowners. But, watering the yard requires an entire household to skip a shower, not wash anything and avoid cleaning. Or, we need to find ways to use a different source of water for irrigation and conserve the potable water for the people.
While the use of reclaimed water for landscape plants has become a standard in many parts of Florida, it has limited availability in the panhandle. However, there are many ways to reduce and conserve potable water use for those with in-ground irrigation systems. First, make sure you have a functional rain shut-off device. By design it will prevent the system from running when it has recently rained. On average, the panhandle has received rain about every 4 days this year. Besides, Florida law requires a rain shut-off device for all irrigation systems, new or old.
Then, calibrate each zone to determine the length of time required to deliver ½ inch of water. This can be determined by placing 10 or more, short, straight-sided containers throughout the irrigation zone. Run the system and look at each container, measuring the depth with a ruler. Adjust the run time so the system only delivers ½ inch. Now set the clock to run 2-3 times a week for that length of time. It’s that simple. And the water savings is significant. For these and many other irrigation tips, visit askIFAS at https://edis.ifas.ufl.edu/.
Mosquitoes are a pesky nuisance we’re all too familiar with, especially as we move into the summer months. Their presence can certainly make being outdoors undesirable. Not only are they a blood-sucking nuisance but they also carry and can transmit many diseases to humans. Mosquito-borne diseases of public health concern in Florida include St. Louis encephalitis, eastern equine encephalitis, West Nile virus encephalitis, dengue, and Zika. While it can be difficult to eliminate mosquito populations completely, there are steps we can all take to protect ourselves and to prevent our landscape from becoming a major breeding ground for mosquitos.
Asian Tiger Mosquito. Photo Credit: James Newman. UF/IFAS Photo.
Source Reduction
One way to keep mosquito populations down is to prevent the landscape from being a breeding ground for them. Many species of mosquitoes require standing water to lay their eggs; therefore, eliminating standing water can help keep populations low. Mosquitoes can develop in a variety of water-holding containers such as flowerpots, birdbaths, pet dishes, tree holes, bamboo trunks, and many others. It is important to:
Drain water from garbage cans, gutters, buckets, coolers, or any other containers where water is collected
Discard any old tires, bottles, broken appliances, or items not being used that could potentially hold water
Change water in birdbaths and/or outdoor pet dishes once or twice a week
Mosquito larvae. UF/IFAS File Photo
For areas such as ornamental ponds or water gardens, aeration or stocking them with mosquitofish (Gambusia species) can also help to keep mosquito populations down. The small fish will feed on the mosquito larvae and add movement to the water. They are most effective in small ponds with no other fish present.
For other areas with standing water that cannot be drained, such as rain barrels or ornamental ponds, products containing Bacillus thuringiensisisraelensis (Bti) are effective in controlling mosquito larvae. Products containing Bti come in the form of granules or “dunks”, which look like miniature donuts. These Bti products are considered a form of biological control as it is a naturally occurring bacteria that is specific to mosquito, blackfly, and fungus gnat larvae. Therefore, Bti products are not harmful to fish, waterfowl, pets or humans when used according to label directions.
Protective Clothing and Repellents
The most effective way to protect yourself from mosquito bites is to avoid infested areas, wear protective clothing, and wear insect repellent when outdoors. There are several repellents that are currently available such as DEET, picaridin, and IR3535, or plant derived chemicals such as citronella and oil of lemon eucalyptus.
It is important to read the label before applying mosquito repellent and to remember that there are different recommendations for frequency of application for different products. Below is a table comparison of products based upon University of Florida research.
Potting soil, potting mix, garden soil, topsoil. The bags are all sitting side-by-side on the shelf at the garden center. Your challenge is to figure out which one you need for your project. What’s the difference? To begin with, none of them are dirt. The Soil Science Society of America defines dirt as “displaced soil”, the dead nuisance material left on your hands after working with soil. Soil is a blend of sand, silt, clay and organic matter. It is alive with nutrient and water holding components. But, all soil is not equal.
Soil contains decayed organic remains. It may be composted leaf tissue and/or microorganisms. The terms potting soil and potting mix are often used interchangeably, but there is a significant difference. Potting soil contains compost or the flora responsible for the breakdown process. Potting mix is soil-less. It is a blend of sphagnum moss, coir, bark, perlite and/or vermiculite. While these are natural occurring materials, they are in their original state. No decomposition has occurred. In the absence of compost, the resulting potting mix is sterile and free of fungus spores and insect eggs. Potting mixes are excellent choices for container growing, especially for house plants. The sphagnum moss, coir and bark hold and release water and nutrients, while the vermiculite or perlite keep the mix loose and well-drained. Some blended products add microbes, which then requires the word soil be added to the packaging. These are still suitable for potted plants.
But, if the potting soil is made from mostly compost, the potential of having poor drainage and fungus gnat problems increases substantially. The only containers these type of potting soils should be used in are raised gardens. Depending on the compost source, these soils can sour, grow mushrooms or become extremely hard.
Garden soil is a blend of soil and soilless ingredients. It can be used in very large containers (24” or greater) or added to native soils to enrich planting areas.
Then there is topsoil. It varies widely in composition and quality. Use it to fill holes in the yard, build berms or mix it will compost to increase water retention in dry garden areas.
So, when standing in the store comparing prices, don’t let price dictate your purchase. To keep your containerized plants doing well, do some bag reading. Choose the product that has aged forest products, sphagnum moss and perlite. Use the soils made from bio-solids and composted materials to improve the sand in the yard. When you’re done, go wash the dirt off your hands.
potting mix are often used interchangeably, but there is a significant difference. Potting soil contains compost or the flora responsible for the breakdown process. Potting mix is soil-less. It is a blend of sphagnum moss, coir, bark, perlite and/or vermiculite. While these are natural occurring materials, they are in their original state. No decomposition has occurred. In the absence of compost, the resulting potting mix is sterile and free of fungus spores and insect eggs. Potting mixes are excellent choices for container growing, especially for house plants. The sphagnum moss, coir and bark hold and release water and nutrients, while the vermiculite or perlite keep the mix loose and well-drained. Some blended products add microbes, which then requires the word soil be added to the packaging. These are still suitable for potted plants.
