Large Patch: Not the Only Rhizoctonia in Town

Large Patch: Not the Only Rhizoctonia in Town

Large patch Rhizoctonia solani (known as brown patch in cool season grasses) is a common disease of many turfgrass species.  It usually occurs during the cooler months from October through May when temperatures are below 80 degrees Fahrenheit.  However, signs and symptoms of large patch and other Rhizoctonia diseases can be observed throughout the summer.  Less common Rhizoctonia species that occur during the summer months are Rhizoctoni zeae and Rhizoctonia oryzae.  Extended periods of turf wetness from excessive rainfall or overwatering provide ideal conditions for the disease to develop and spread.

Rhizoctonia in zoysiagrass

Rhizoctonia in a zoysiagrass lawn. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

This summer in Santa Rosa County, Rhizoctonia has been positively diagnosed in both St. Augustinegrass and zoysiagrass lawns and suspected in a number of centipedegrass lawns.  The disease usually starts as small, yellow patches (about a foot in diameter) that turn reddish brown, brown, or straw colored as the leaves start to die. Patches often expand to several feet in diameter.  It is common to see rings of yellow or brown turf with otherwise healthy turf in the center.  The fungus infects portions of the blades closest to the soil, eventually killing the entire leaf.  Grass blades can easily be pulled off their stems, but roots are not affected by the disease.

Rhizoctonia in a St. Augustinegrass lawn

Rhizoctonia in a St. Augustinegrass lawn. Photo Credit: John Atkins, University of Florida/IFAS Extension – Santa Rosa County

Overwatering and excessive fertilization can both contribute to the development of Rhizoctonia disease.  Improper timing of fertilizer application can also promote disease development.  In the Florida Panhandle, turfgrass is actively growing from April to October.  Slow-release fertilizers are recommended to allow for a more even distribution of nutrients over the course of multiple months.  Recommended fertilizer rates are based on turfgrass species, geographical location, and fertilizer analysis.  Please refer to the UF/IFAS Publication: “Urban Turf Fertilizer Rule for Home Lawn Fertilization” for rate recommendations.

fertilizer chart

Chart excerpted from Florida-Friendly Landscaping publication.

If large patch or another Rhizoctonia disease is confirmed in your lawn, then chemical controls are necessary to keep the disease from spreading.  Fungicide products containing the active ingredients azoxystrobin, chlorothalonil, fludioxonil, flutolanil, iprodione, mancozeb, metconazole, myclobutanil, polyoxin D, propiconazole, thiophanate-methyl, thiram, triadimefon, trifloxystrobin, or triticonazole are viable options for keeping the disease from spreading.  For best results, follow the fungicide label for application instructions.  It’s important to not only treat the affected areas, but also the healthy turf surrounding these areas in order to keep the diseased spots from growing in size.

Unfortunately, turf diseases are often not noticed until large patches of declining and dead turf are noticed.  In these cases when large dead patches exist in the lawn, it is usually necessary to resod these areas.  As with most problems that arise in the landscape, good cultural practices are the most proactive way to mitigate the chances with turfgrass diseases.  The UF/IFAS Florida Friendly Website provides up-to-date solutions and recommendations for caring for Florida landscapes.

July Is Smart Irrigation Month

July Is Smart Irrigation Month

The Irrigation Association (IA) kicks off the official start of this year’s campaign on Tuesday, July 9, 2019. The initiative promotes the social, economic and environmental benefits of efficient irrigation technologies, products and services in landscape, turf and agricultural irrigation.

Irrigation (agricultural and turf/landscape) accounts for 65-70% of total freshwater use in the United States. According to the Environmental Protection Agency’s (EPA) WaterSense program, the average American family household uses more than 300 gallons of water per day; roughly 30% of this occurs outdoors. Efficient landscape irrigation systems and practices dramatically reduce water being lost or wasted.

The starting point for improving the efficiency of a home landscape sprinkler system is to calibrate each zone (http://ufdc.ufl.edu/IR00003389/00001) and make adjustments and repairs. That includes the rain shut-off device.

Florida is one of the few states with a rain sensor law. The most recent version of the statute (2010) states the following: “Any person who operates an automatic landscape irrigation system shall properly install, maintain, and operate technology that inhibits or interrupts operation of the system during periods of sufficient moisture.” (Florida Statute 373.62). Regardless of the water source or age of the system, all in-ground irrigation systems must be connected to a functioning rain sensor of some kind.

Rain collecting device with expanding cork disks inside.

Expanding disk Rain Sensor

Expanded disk devices are the most popular rain sensor due to their low cost, ease of installation, and low maintenance. Traditionally, they are wired into the controller, but a wireless version allows for quicker installation and mounting up to 300 feet from the controller. These “mini-click” sensors contain disks made of cork that absorb rainfall and expand, triggering a pressure switch. The disk cover is rotated to adjust for the predetermined amount of rainfall required to trigger the switch. It should be set on ½ – ¾ inch, depending on soil type and rooting depth of irrigated plants. The switch continues to interrupt the scheduled controller as long as the disks are swollen. When the rain stops, the disks begin to dry out. Once they have contracted, the switch closes and the regularly scheduled irrigation cycle begins where it left off before the interruption. These small cork disks wear out in Florida’s heat and need to be replaced. By checking and repairing the sensor parts, the sprinkler system will operate much more efficiently. We have all seen irrigation systems running in pouring rain.  Keep yours maintained to avoid this needless waste of water.

So, join the kids this summer. Go outside and play in the water. Turn on the sprinkler system and check it out. July is Smart Irrigation Month. Let’s see how efficient you can make your system and reduce the water waste in Florida.

Perennial Peanut Lawn:  Two Years Later

Perennial Peanut Lawn:  Two Years Later

‘Needlepoint’ Perennial Peanut in the author’s lawn.

What began as my journey toward a turf-less lawn in September of 2017 is finally beginning to come together!  In the fall of 2017, I installed about 120 one-gallon-sized ‘Needlepoint’ Perennial Peanut (Arachis glabrata) plants, purchased from Sunset Specialty Groundcovers in Live Oak, FL, on roughly 20” centers in my front lawn, an oddly shaped (650 ft2) patch of ground that had been previously filled with spotty centipedegrass and a healthy and diverse weed population.  18 months later, the peanut has almost completely filled in, shaded out all the weeds, and blooms nonstop!

Looking back, I definitely learned a few lessons the hard way.  First, you should mulch bare ground in between plants at time of installation.  Because there are few herbicides labelled for residential use on this crop and I didn’t want to experiment on my new “lawn”, I spent a lot of time on my hands and knees (much to the amusement of my neighbors and folks driving by) pulling weeds in the first two years that could have been prevented with mulch.  Second, have a plan for keeping the perennial peanut in bounds once it has filled in the area it was supposed to and begins to travel into adjacent landscaped beds!  The area my peanut inhabits is surrounded on two sides by inescapable concrete.  It was on the other two sides, however, that I have had to improvise after they came under siege (literally under, because perennial peanut spreads by underground rhizomes).  Installing some sort of edge blocker at planting and vigilance with routine mechanical edging is a must to keep it in bounds!  Third, I recommend that you have a counter-argument prepared when the peanut goes dormant in the winter and your wife asks why the yard is bare dirt!

‘Needlepoint’ Perennial Peanut overhead shot showing complete ground coverage in the author’s lawn.

Overall, though there are a couple of things I would have done differently, I’m extremely pleased with my lawn of perennial peanut.  It is absolutely stunning in the warm months, incredibly low maintenance, and unique!  Plant some today!

As always, if you have any questions about perennial peanut or any other plant/crop, contact your local UF/IFAS Extension office.

Best Time to Control Mole Crickets, If Needed

Best Time to Control Mole Crickets, If Needed

Adult and nymphs of mole crickets. Photo: Julie McConnell, UF/IFAS

The best time to treat for mole crickets is during June through July. But don’t treat at all if mole crickets have not been positively found and identified in the affected lawn areas.

Don’t worry about the adults that are seen flying around lights in the evenings or about the mole crickets found dead in swimming pools this time of year. They are in a mating phase and are doing very little to no damage to lawns during late winter and spring.

We can take advantage of the fact that there’s only one generation per year in North Florida. The eggs will have all hatched by mid to late June. At that time, you’re dealing with young mole crickets that can’t fly and that are much more susceptible to the insecticides designed to kill them. Mole crickets spend winter as adults in the soil. In late February and March, adults emerge and begin mating. Shortly after mating, males die and females fly to suitable areas for egg laying. Mated females deposit eggs in tunnels. After depositing her eggs the female dies. Attempting to control adult mole crickets during this mating period a waste of time, money and product. Plus, adult mole crickets are difficult to control and can easily fly out of treated areas.

You can easily determine if mole crickets are the cause for your lawn problem by flushing them out with a soap and water mixture.

Mix 1½ ounces of a lemon scented liquid dish-washing soap in two gallons of water in a sprinkling can or bucket. Pour the soapy water over an area approximately four square feet and count the number of mole crickets that emerge. It only takes several minutes for mole crickets to crawl to the surface after the soap treatment if they are present. Repeat the process around the yard where you suspect mole cricket problems. If you flush an average of two to four crickets are flushed out per site, control may be needed.

There are a number of insecticides on the market to control mole crickets. But before using any product, first identify the problem as mole cricket damage by using the soap flush technique. Then choose a lawn insecticide that lists mole crickets on its label. And finally read the label carefully for use directions, application techniques, irrigation requirements and precautions.

For more information on mole crickets, including recommended insecticides and other non-chemical control options, contact the UF/IFAS Extension Office in your County or access the following links.

Insect Pest Management on Turfgrass

Shortwinged Molecricket 

Mole Cricket IPM Guide for Florida 

Summer Annual Weeds Thriving in Panhandle Lawns

Summer Annual Weeds Thriving in Panhandle Lawns

Figure 1: Chamberbitter, a common annual weed.
Credit: Mary Salinas, UF/IFAS Extension Santa Rosa County.

With daily rainfall occurring regularly, coupled with humid temperatures, summer annual weeds have had a mighty boost in growth. Chamberbitter, Florida pusley, sedge and oxalis are just some examples of the many weeds that are  exploding across our landscape.

Chamberbitter (Phyllanthus urinaria) is found as north as Illinois and as west as Texas, but thrives in lower southeastern states. It’s a headache for homeowners as well as pasture managers. The foliage resembles that of the mimosa tree (Albizia julibrissin) and can be confused with the native mimosa groundcover, known as powderpuff mimosa (Mimosa strigillosa). This plant grows upright and develops a long taproot. Wart-like seeds can be found on the underside of the branch.

Florida Pusley (Richardia scabra L.) also known as Florida snow or Mexican clover, has recently blanketed landscapes in the Panhandle with white flowers. It’s a persistent weed that moves quickly.

Sedges and sedge-like plants (Cyperus ssp.), known as kyllinga, are species that emerge in late spring and thrive in summer months in warm, moist climates. Excessive irrigation or areas with poor drainage create a very hospitable environment for these weeds. Sedges are annual grass-like plants have an elaborate flower-bearing stems. Yellow and purple nutsedge are the most common species. Kyllingas have smaller leaves and are less vertical. Sedges and kyllingas are fast spreading, and reproduce through seed and rhizomes, or underground tubers.

Oxalis or yellow woodsorrel (Oxalis stricta) have heart-shaped lobes and have a bright yellow flower. Oxalis reproduces by seed and have a narrow “okra-like” seed pod.

Figure 1: (L to R) Chamberbitter, Pusley, Sedge, Kyllinga & Oxalis.

Credit: Stephen H. Brown, UF/IFAS Extension Lee County

What about control? Some cultural control methods are hand removal and mowing frequently to offset the life cycle, but these practices alone will most likely not solve the problem. There are many broad spectrum herbicides that can be used to control these weeds with good results, but you must be persistent. Some are season long applied products. However, most effective products need to be applied in cooler temps than we have now. Consecutive days of temperatures of less than 90 degrees would be optimal. Applying the chemical otherwise will most likely harm the turfgrass. Be aware, some productions will injure or kill centipede and St. Augustine, but are safe to use on other turfgrasses like bermuda, bahia and zoysia. Be sure to read the label and follow the directions and precautions.

Another option is non-selective herbicides, like glyphosate, which can be used in thick patches or for spot treatment. When using a selective herbicide, remember to protect turfgrass and other plants from spray drift or any contact, especially regarding ornamental plants and trees.

Contact your local county extension office for more information.

Supporting information for this article is from the following online publications:

Clemson Cooperative Extension publication: “Chamberbitter”, Bulletin HCIC 2314: http://www.clemson.edu/extension/hgic/pests/pdf/hgic2314.pdf

UT Institute of Agriculture document, “Nutsedge and Kyllinga Species” by Mathew T. Elmore, James T. Brosnan and Gregory K. Breeden: http://www.tennesseeturfgrassweeds.org/Lists/Fact%20Sheets/Attachments/23/W260updated2015.pdf

UF/IFAS EDIS publications: “Yellow Woodsorrel (Oxalis) Biology and Management in Turf” by J. Bryan Unruh, Ramon G. Leon, and Darcy E. P. Telenko: http://edis.ifas.ufl.edu/pdffiles/EP/EP38500.pdf

“Weed Management Guide for Florida Lawns” by J. Bryan Unruh, Ramon G. Leon, Barry J. Brecke, and Laurie E. Trenholm: http://edis.ifas.ufl.edu/pdffiles/EP/EP14100.pdf

UF/IFAS Extension is an Equal Opportunity Institution.