by Matt Lollar | Aug 1, 2019
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 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. 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.
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.
by Daniel J. Leonard | Jun 25, 2019
‘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.
by Larry Williams | Jun 25, 2019
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
by Matt Lollar | Apr 9, 2019
The Evidenced-Based Zoysiagrass Management Workshop is returning to Milton on April 23 at the University of Florida – Milton Campus. Attend to get updates on managing zoysiagrass and to earn CEUs. Register at: UF/IFAS Evidence-Based Zoysiagrass Workshop
by Sheila Dunning | Aug 2, 2018
Although it has been very hot this summer throughout the Florida Panhandle, many areas have been blessed with afternoon showers several day in a row. Historically, this has been the typical Northwest Florida weather pattern known as the ‘Dog Days’. 
Yet, many landscape sprinkler systems were still running. One has to ask, “Where are all the rain shut-off devices?”. Florida is one of just a few states with a rain sensor statute. Since May 1991, new installations of irrigation systems have been required to include a rain shut-off device. However, no wording was included to cover installation or maintenance. The 2010 statute change now states the following: “Any person who operates an automatic landscape 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).
Thus, ALL automatic landscape irrigation systems require rain sensors, or other shut-off devices such as soil moisture sensor irrigation controllers. No “grandfather clause” was included for existing systems. Regardless of when it was installed, every sprinkler system must have an operational rain shut-off device. Irrigation contractors can be fined for working on a system without checking out and/or connecting a device.
Moisture sensing technology conserves water, saves money, reduces wear on irrigation system components, reduces disease and helps protect water resources from runoff. Previous research has shown that homeowners using in-ground, automatic irrigation systems, typically in Florida, apply 47% more water for landscape irrigation than homeowners without automatic irrigation systems. This over-irrigation is largely due to a “set it and forget it” mentality despite seasonal fluctuations in plant water needs. If the water costs and the amount of water applied per watering cycle are known, it is easy to calculate how much money is being saved each time the sensor interrupts the program. For example, if a system irrigates ½ acre of turf and is set to deliver ½ inch of water to each zone, approximately 13,576 gallons of water will be used during each watering event. If the cost of the water is $2.00 per thousand gallons, every time the sprinkler system comes on the water bill will be $27.15. A significant amount of money and water can be saved by maintaining a rain shut-off device.
Irrigation is common in Florida landscapes because of sporadic rainfall and the low water holding capacity of sandy soils. Water conservation is a growing issue due to increased demands from a growing population. The least expensive and most common rain sensor device is the expansion disk rain shut-off. Expanding cork disks trigger a pressure switch. The expansion space can be easily adjusted by rotation of the disk cover to a predetermined amount of rain required to trigger the switch. The amount of rain that will interrupt the irrigation system is marked on the adjustment cap. A rain sensor must be mounted where it will be exposed to unobstructed rainfall, typically installed near the roofline on the side of a building.
Irrigation control technology that improves water application efficiency is now available. Soil moisture sensors (SMS) can reduce the number of unnecessary irrigation events. Most soil moisture sensors are designed to estimate soil volumetric water content based on the soil’s ability to transmit electricity, which increases as the water content of the soil increases. Bypass type soil moisture irrigation controllers use water content information from the sensor to either allow or bypass scheduled irrigation cycles on the irrigation timer. Another type of control technique with SMS devices is “on-demand” where the controller initiates irrigation at a low threshold and terminates irrigation at a high threshold. A single sensor can be used to control the irrigation for many zones or multiple sensors can be used to irrigate individual zones. In the case of one sensor for several zones, the zone that is normally the driest, or most in need of irrigation, is selected for placement of the sensor in order to ensure adequate irrigation in all zones. Sensors should be buried in the root zone of the plants to be irrigated. For turfgrass, the sensor should typically be buried at about three inches deep. The placement of SMS should be at least 5 feet from hard surfaces and sprinkler heads. The sensor needs to be calibrated and/or the soil water content threshold needs to be selected.
The amount of water that can be saved using rain shut-off devices is substantial since water use increases substantially during summer months. Remember that every drop that hits the ground will be picking up pollutants as it flows to our groundwater. Nonpoint source pollution is the leading cause of water quality problems. These pollutants have harmful effects on drinking water supplies, recreation, fisheries and wildlife. By only irrigating when the soil needs it, you are also preventing contamination of drinking water.
This article is being reissued as part of our ‘Best Of” series, from August 2013 .
