by Beth Bolles | Jan 17, 2017
It won’t be long before homeowners start thinking about sodding a new lawn or renovating areas of their existing turf. Although sodding when turf is dormant is acceptable, it is best to install sod that is green. One reason is that you can see if any sod pieces are infested with weeds such as bermudagrass . This perennial grass is very difficult to manage once it becomes established in centipede, St. Augustine, or zoysiagrass. Always remove turf pieces with bermudagrass during the installation process to prevent it from taking over a patch of your new lawn.
Bermudagrass growing in a piece of centipede sod. This piece should have been removed during installation to prevent the bermudagrass from taking over a patch of new centipede lawn. Photo by Beth Bolles, UFAS IFAS Escambia County Extension
If you have a piece of turf or a small area where common bermudagrass has emerged in your desirable grass, take care of the issue as soon as it is seen. The best option is dig out the infested area making sure that you get the underground runners of the bermudagrass. Smooth out the bare soil and then install new sod pieces. You may have to hand water these pieces as needed since the surrounding turf will already be established.
by Carrie Stevenson | Oct 12, 2016
Dr. Ramon Leon, Extension Weed Specialist, West Florida Research and Education Center
Herbicides simplify weed management by allowing you to cover extensive areas in a relatively short time, and reduce the need for time-consuming control practices such as hand weeding. Additionally, many herbicides have the advantage of selective control. Selective herbicides are those that kill weeds without significantly injuring the desired plant. In turfgrass, selective herbicides are particularly important because we do not have the option of using cultivation or non-selective herbicides, as is commonly done in other agricultural systems such as row crops and orchards.
A common misconception is that when a herbicide is registered for use on a given turfgrass species, this herbicide has little negative effect on the turf. In reality, even when the herbicide is registered for a specific turfgrass species, it can cause a certain level of injury. If the herbicide is applied at the recommended label rate, and the growing conditions are ideal, the turfgrass will only suffer minor, temporary injury that may go completely unnoticed. Conversely, the weeds that are susceptible to the herbicide will be severely affected resulting in the desired control.
Over the last few summers, there has been an increase in complaints about herbicide injury on sod farms, golf courses, and home lawns after applications of herbicides, especially during the summer months. Many of those complaints originated from situations in which the application was done properly, using the recommended label rate, and thus the level of injury observed was not justified. After studying all these cases, it was determined that at the time of herbicide application the turf was under a moderate level of stress, but not high enough stress to cause visible symptoms. However, when the herbicide was applied the combined effect of the existing stress, and the stress caused by the herbicide made it harder for the turf to maintain the desired quality. For example, Figure 1 below shows that the turf looked fine before the application (A), but after the herbicide was applied, there was a significant loss in turf cover and quality (B). The interesting aspect is that the injury was not present across the entire treated area, but only on patches (C). Those patches corresponded with sand pockets where soil moisture, especially on hot days, was considerably lower than the rest of the area. In that particular case, the irrigation system was providing enough water to help the turf tolerate the moderate stress of high temperatures and limited moisture, but not enough for the turf tolerate the combined stress that occurred after the herbicide was applied.
Figure 1. Centipedegrass growing during the summer in Florida before herbicide application (A), 3 weeks after herbicide (sulfentrazone and metsulfuron-methyl) application (B). Herbicide injury pattern with highlighted areas showing where sand pockets caused drought and heat stress that contributed to herbicide injury (C).
In Florida, there are a combination of environmental factors such as high temperatures and sandy soils that can create stressful conditions limiting turfgrass growth, especially when irrigation is not sufficient to keep the turf hydrated. Furthermore, we also experience periods of excess rainfall, and areas of turf growing under shade. Additionally, pest problems that affect roots and leaves are frequently found in our state. All these conditions affect turfgrass health and its ability to tolerate herbicide applications. For these reasons, turf producers and managers need to be proactive to help turfgrass overcome the injury that herbicides might cause. To achieve this goal, you need to follow five simple steps:
1) Identify weed problems early. Most weed problems will start in the spring for summer weeds and in the fall for winter weeds. Controlling them when they are small not only increases the effectiveness of our applications, but also allows us to implement our control when the turfgrass is less likely to be stressed.
If herbicide applications are needed when conditions might be stressful for the turf (high temperatures and/or dry conditions)
2) Make sure irrigation is adequate (increase frequency or duration if needed) for up to three weeks following application.
3) Reduce mowing frequency and increase mowing height 0.5 inches for up to 3 weeks following a herbicide application, to allow the turfgrass to continue producing energy to support its recovery. Mowing too short and too frequently immediately after the application weakens the turfgrass.
4) Fertilize with a small amount of nitrogen (0.25 to 0.5 lb N/acre) a week or two after herbicide application to help the turf recover and produce new leaves.
5) If the turfgrass is suffering from serious pest problems (pathogens, nematodes or insect infestations) do not apply herbicides on the affected areas until the turfgrass has recovered.
Maintaining optimal turfgrass growth is the best way to ensure that herbicide applications will maximize weed control while still protecting the health and aesthetics of your turfgrass.
For more information on growing turfgrass in Florida, please see the following:
Dr. Ramon Leon, Extension Weed Specialist, West Florida Research and Education Center
by Matt Lollar | Sep 29, 2016
Tropical sod webworms (Herpetogramma phaeopteralis) have recently been encountered in a number of yards in the Panhandle. The worms usually feed in large groups and unfortunately, the first, and basically the only, sign of damage is often a large area of shorter grass due to their feeding. The arrival time of sod webworms is also unfortunate because they are part of a group of caterpillars that successively attack turf including fall armyworm (Spodoptera frugiperda), striped grass loopers (Mocisspp.), and the fiery skipper (Hylephila phyleus).
Sod webworm feeding damage in the turf thatch layer. Photo Credit: University of Florida/IFAS Extension.
Description
Larvae
Caterpillars are light yellow to orange with brown spots on each body segment and they have a dark, orange-brown head. They will grow to a full length of slight less than 1/2 inch.
Pupae
The reddish brown pupae are about about 1/4 inch long. The pupae are typically found in the upper thatch layer.
Pupa found in cocoon in St. Augustinegrass thatch. Photo Credit: Steven Arthurs, University of Florida/IFAS
Adults
The moths brown with splotchy wings and are about 3/4 inch wide.
Control
Sod webworms are difficult to control because of their spontaneity. However, in the lawn they hide in the thatch during the heat of the day. Over watering and fertilization can increase the amount of thatch. It is important to follow UF/IFAS guidelines for home lawn management.
The first line of defence is healthy turf. Proper fertilization, irrigation, and mowing height can decrease susceptibility of turfgrass against sod webworm. Over-fertilization is a common cause of caterpillar outbreaks in lawns. Cultural practices such as thatch removal by vertical mowing can help eliminate populations. Eggs are laid on grass blades and removal of grass clippings might also reduce populations.
Numerous chemical control options are available, but softer chemicals such as insecticides containing the bacteria Bacillus thuringiensis are recommended as a first line of defense. Insecticides should be applied in the morning or evening during feeding time. For additional control strategies and basic information please visit the UF/IFAS Sod Webworm Publication.
by Blake Thaxton | Sep 29, 2016
St. Augustinegrass roots rotted due to take-all root rot. (Photo Credit: IFAS Photos)
The crisp air of fall is upon us. Maybe. We live in northwest Florida and we are not experiencing the change in weather just yet. With the change in weather coming, we are having specific issues in turfgrass lawns and are sure to have others in the near future. Extension agents in the western panhandle have come into contact with several St. Augustine lawns with symptoms and signs of take-all root rot (Gaeumannomyces graminis var. graminis) and we can soon expect with cooler temperatures for Large Patch to be rearing its ugly head.
Early aboveground symptoms of take-all root rot. (Photo Credit: IFAS Photos)
Take-all root rot is sometimes referred to as a “stress disease”, as it is brought on by stressful weather conditions and improper management. Periods of rainfall can provide conditions for the disease to affect all warm season grasses. Other stresses such as improper mowing height, improper irrigation, and improper fertilization can worsen the situation. For example, St. Augustinegrass, except dwarf cultivars, should be mowed at 3.5 to 4 inches and the mower should never remove more than 1/3 of the leaf blade at any cutting. With the current high temperatures and prolonged periods of rainfall it can be difficult to follow this practice. When a homeowner does not mow the lawn in a timely manner and lets the lawn grass get much too high and cuts more than 1/3 of the grass blade, this can become a stress to the lawn. Fungicide sprays can be made during favorable environmental conditions, before symptoms are seen to protect from infection with take-all root rot for high valued properties. To learn more about take-all root rot refer to this University of Florida/IFAS Extension publication: Take-all Root Rot
With the fall weather coming, please be sure to read and learn about large patch disease as well. This can brought on by temperatures of less than 80 degrees and high humidity or extended periods of rainfall. Read the University of Florida/IFAS Extension publication for more information: Large Patch
For any other information needed regarding proper lawn management, please visit Your Florida Lawn or contact your local UF/IFAS Extension office.
by Ray Bodrey | Sep 8, 2016
Driving through rural panhandle counties this time of year, one finds pastures with thick green canopies, exploding with yellow-gold flowers. Perennial peanut is in bloom. This is a highly nutritional forage option for livestock and also makes for a beautiful urban groundcover alternative to turfgrass.
Perennial Peanut Field. Photo credit: Ray Bodrey, UF/IFAS.
Perennial peanut was introduced from Brazil in the mid 1930’s. Though a non-native, the perennial peanut has not been shown to be a nuisance nor an invasive. The plant is in the same genus as the peanut that humans consume. However, this plant is a true perennial, living year to year. Perennial peanut does produce a small seed pod. But rhizoma perennial peanut, Arachis glabrata, does not reproduce by seed. Therefore, wildlife, specifically birds, are unable to disburse the plant into unintended areas.
As a side note, few perennial peanut cultivars, such as Arachis pintoi or “pinto peanut”, can be planted by seed. This species has stolons or “runners” and will produce adventitious roots at the nodes. The pinto peanut has become confused in nursery trade with the Florida-developed perennial peanut. Limited research to date has shown how well pinto peanuts perform as groundcover. The pinto peanut is more susceptible to winter kill, insect damage and nematodes than the cultivar Arachis glabrata.
The Florida developed perennial peanut is used mostly for hay or grazing by livestock such as horses, beef & dairy cattle, sheep and goats, as well as wildlife such as deer, rabbits and turkeys. The most common cultivars for pastures are “Florigrazed” and “Arbook”. These cultivars were released by UF IFAS and USDA in 1978 and in 1985. Since the release, these cultivars have also has been used in citrus groves as a cover crop as well as a ground cover in roadway medians. In Florida, it has been planted on approximately 30,000 acres.
Perennial peanut is high in nutritional value and is easily digestible by forage animals. It’s also a nitrogen fixer. Like all legumes, perennial peanut obtains its nitrogen from a bacteria associated with the plant’s root system. Therefore, it naturally adds nitrogen to the soil, reducing the amount of fertilizer needed if used with other crops or plants in a landscape.
Perennial peanut will reach ½ – 1 ½ feet in height. The plant is propagated using rhizomes and can be purchased as mats of sod or in containers. With its extensive root system, rhizoma perennial peanut spreads across the ground as a sod grass would perform. Perennial peanut grows best in sandy to sandy loam soils with a target soil pH of 6.0 although a soil range of 5.8 – 7.0 is adequate. It requires high moisture, with at least 30 inches of rain per year.
In home landscapes, several cultivars are available and have limited maintenance issues. “Ecoturf” and “Arblick” are the most popular cultivars used due to their lower height and profuse flowering. These cultivars thrive in coastal areas as they are considered salt tolerant. Salt spray, drift and short term salt water flooding have little effect. Mowing is not required but edging may be needed as the plant spreads. Weed control is the most concerning, especially during establishment. For pest management, peanut stunt virus cases have been reported. The symptoms are leaf mottling and yield depressions, but are rarely a problem unless the plant is under drought or nutrient stress.
All information considered, perennial peanut is a great option for panhandle livestock producers or the home landscape enthusiast.
Supporting information for this article can be found in the UF/IFAS EDIS publications:
“Guide to Using Rhizomal Perennial Peanut in the Urban Landscape”, by Robert E. Rouse, Elan M. Miavitz and Fritz M. Roka.
“Rhizoma Perennial Peanut”, by M.J. Williams, Y.C. Newman and Ann Blount.
“Perennial Peanut: A Quick Reference”, by Yoana C. Newman, Cheryl L. Mackowiak, Ann R. Blount and Jason Ferrell.
“Plant Materials Fact Sheet: Rhizoma Perennial Peanut (Arachis glabrata) – The Perennial Peanut for Urban Conservation in Florida”, by USDA NRCS.
by Carrie Stevenson | Jul 19, 2016
Florida home and yard. Home, house, stone pavers, walkway, yard, landscaping. UF/IFAS Photo: Tyler Jones
Dr. Ramon Leon, Extension Weed Specialist, West Florida REC, Jay
Last year the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) classified glyphosate as “probably carcinogenic to humans.” This generated a lot of controversy because the Environmental Protection Agency (EPA), the European Food Safety Authority, and recently a joint report between the Food and Agriculture Organization (FAO) and WHO concluded that glyphosate is unlikely to be carcinogenic in humans.
As a University of Florida/IFAS Weed Specialist, I have been receiving multiple phone calls and e-mails from homeowners, homeowner associations (HOA), lawn care companies and contractors, municipalities, and county managers requesting a list of herbicides that are “safer” than glyphosate. When I ask them the reason for this particular preference, all of them acknowledged that their concern originated from hearing about the IARC report.
The first point that I always explain to people concerned about this issue is that most of the scientific evidence indicates that glyphosate does not have a higher carcinogenic risk compared to many other substances that they are normally exposed to in their daily activities. The second point is that it is important to continuously monitor how chemicals we use affect our health and the environment in the long run. The IARC report is a reminder that we should keep a close eye on glyphosate, the most widely used herbicide in the world, but it is not necessarily a call to stop using it, because at this point there is no direct evidence that it causes cancer in humans.
Very frequently, regardless of the technical details, many homeowners and citizens in urban areas are considering not using glyphosate in their gardens and landscapes, and they would like to use “safer” herbicides.
What do you mean by “safer?”
If you mean lower risk as a carcinogen, then most herbicides registered for use in urban areas would be acceptable because none of them are considered “probably carcinogenic” by IARC or any other regulatory agency. Therefore, you have multiple options to choose from. However, many of the conversations have lead to the statement, “No, I want something that is less toxic than glyphosate!”
Toxicity in pesticides is predominantly assessed using the lethal dose 50 (LD50), which indicates the amount of a chemical that kills 50% of a reference population of test animals (e.g. mice, rabbits, rats). When the LD50 is high, this means that the chemical has low toxicity, and when the LD50 is low it is considered that toxicity is higher because small amounts of the chemical can cause mortality. Glyphosate has one of the highest LD50s for herbicides. In other words, glyphosate is one of the least toxic herbicides available based on the LD50 standard. Therefore, if we want an alternative herbicide that is less toxic, we do not have any options for urban areas.
What about organic herbicides?
Many people associate “organic” with “safer.” This can be misleading because it depends on how safety is measured. For example, there are multiple organic herbicides that are considered to have the same or even higher toxicity when compared with glyphosate, because many of them have irritant and corrosive properties. Furthermore, organic herbicides have dramatically different herbicidal properties that make them unlikely alternatives to effectively replace glyphosate.
Glyphosate has one of the broadest spectrums of control, so it kills many different weed species effectively. Also, glyphosate works systemically. This means that it is absorbed by leaves and then moves inside the plant to growing points, roots, and other propagating structures. This systemic effect increases the ability to kill relatively large plants. In contrast, the majority of organic herbicides have a contact effect, so they only kill the tissue they touch without being able to move inside the plant. Therefore, they are effective at killing very small plants (<2 inches tall). Large plants can suffer leaf burning after treatment with organic herbicides, and if the application is done properly, the user will see a lot of control shortly after the application (Fig. 1). However, the plants will soon recover and the control level will decrease because, unlike plants treated with systemic herbicides, they can produce new growth from tissues that were not directly expose to the herbicide.
Figure 1. White clover (4 inches tall) control after treatment with glyphosate and twelve different organic herbicides based on natural oil extracts from plants. The green bars represent the level of control 7 days after treatment (DAT) and the yellow bars indicate control 21 DAT.
Considering the lack of alternatives to replace glyphosate, if you want to stop using this herbicide, and you do not want to use any other synthetic herbicides, because their toxicity might be higher, then you need to recognize that weed management will be more challenging. It is unfair to ask lawn care companies or members of HOAs to stop using the tools they have to control weeds and yet expect “weed free” lawns, gardens, and landscapes. Controlling weeds in these scenarios without glyphosate and other synthetic herbicides will require more intensive use of mechanical control approaches and hand weeding. Also, if relying on organic herbicides, these herbicides will have to be frequently applied (probably once or twice a week) in order to kill the weeds at the right time (before they get too big). Also, all these activities will increase weed control costs and the results will likely be not as satisfactory. Thus, you might end up paying more to have lawns and landscapes that will have more weeds escaping control. If this is not acceptable to you, then you probably should be more open to consider the weed control tools we have available. Also, you should be more vigilant about what are the appropriate ways to use them to minimize their risks to humans and the environment, while obtaining the benefits that you are seeking. Otherwise, you should get used to seeing more weeds in the landscape, and to be fair… this might not be as bad as some people think.
