November 9th Green Industries Best Management Practices Class
Wednesday November 9th, 8am-4pm. Green Industries Best Management Practices
Okaloosa County Extension 3098 Airport Rd. Crestview, FL. Click Here for flyer.
Perennial Peanut, a Great Choice for Panhandle Pastures and Landscapes
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.
Tropical Sod Webworms Active in Local Lawns
Tropical sod webworms have been active in local lawns during the past few weeks here in North Florida. All of our warm season turf grasses are susceptible to these pests.
Sod webworms are not consistently a problem every year. Some years their numbers are low enough that they are not a problem. Some years we do not see them at all. Those years when they are a problem, it’s usually not until late summer and early fall that they become active and they may continue to feed on lawns until frost occurs.
Fall armyworm. Photo credit: Frank Peairs Colorado State University, bugwood.org.
Fall armyworms and sod webworms can attack at the same time. Sod webworms are the smaller of the two species, reaching a length of about ¾ inch. Armyworms grow to ½ inch in length. Both of these caterpillars are greenish when young, turning brown at maturity. Armyworms generally have a light mid-stripe along their back with darker bands on either side of the mid-stripe. Their feeding is similar, resulting in notched or ragged leaf edges.
Sod webworms tend to feed in patches while armyworms cause more scattered damage. Sod webworms feed at night while armyworms will be seen feeding during the day. Sod webworm caterpillars rest, curled up near the soil surface during the day. Adults of both species are fairly small grayish to brown moths.
If your lawn has damaged spots, look closely for notched leaf blades from their chewing. You may first notice a patch in your lawn that looks like it has been mowed extra low. Closer inspection reveals grass blades that are chewed away. Caterpillar feeding on zoysiagrass shows up more as translucent whitish tan areas on the surface of individual blades more so than as notched blades.
Fall armyworms and sod webworms can be controlled with the same insecticides as the other lawn insects. But you also may use insecticides that contain Bacillus thuringiensis; a bacterium that only kills caterpillars. Control should only be directed against the caterpillars, not the non-feeding, flying adult moths. Always follow the label directions and precautions for any pesticide you use.
For more information on lawn caterpillars contact the UF/IFAS Extension Office in your County or visit http://edis.ifas.ufl.edu/topic_tropical_sod_webworm.
When is Half an Inch a Big Deal?
Sometimes when we talk about the size of things we like to estimate and don’t worry too much about being precise, but there are times when as little as a half inch really is a big deal. When talking about landscape maintenance and pest management that half inch can be crucial.
Here are three examples of when less than an inch may be significant.
Bermudagrass lawn cut at half-inch different height. Photo: Julie McConnell, UF/IFAS
Mowing your turf. If you read Mowing Matters last month, you saw mowing height recommendations for common turf types grown in north Florida. We gave a range of heights, but besides referring to the handy chart, you need to pay attention to your specific site. If you begin to mow and the current setting is too low, shut down the mower and adjust the height.
In this picture you can see that just raising the deck up one-half inch prevented the entire yard from being scalped and put under additional stress. After less than a week of proper irrigation the scalped area recovered and the yard looked uniform to casual inspection.
Treating Mole Crickets. The common knee-jerk reaction to seeing adult mole crickets during a mating flight is to treat the lawn. However, when you see the adults they are past the stage of being susceptible to most pesticide treatments. It is also too early to target the next generation – after all you are witnessing mating flights, so time is needed for egg maturation, hatching, and nymph development and feeding before treatment will be effective. Depending on several factors such as temperature and soil moisture nymphs will become active anywhere from 2 weeks to 2 months after adults are seen.
Adult and nymphs of mole crickets. Photo: Julie McConnell, UF/IFAS
Before applying any pesticides, be sure to scout for appropriate life stage (nymphs approximately ½ inch long) and action thresholds of mole crickets by performing a soap flush (details can be found here Mole Cricket IPM Guide for Florida).
Turf Irrigation. It is important to calibrate your irrigation system and make sure that each turfgrass zone is putting out a minimum of one-half inch of water uniformly.
Why this amount? Research has shown that in most Florida soils application of one inch of water will reach the top twelve inches of soil. Healthy turfgrass roots are typically found in the top 4-6 inches of soil, so by applying one half-inch of water per irrigation cycle you should deliver water to turf roots.
To see an example of how to calibrate your system watch this short video demonstration by Dr. Laurie Trenholm, UF/IFAS Turfgrass specialist.
Challenges for Use of Glyphosate Alternatives in Urban Landscapes
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.
Do Your Plants have Problems?
When you don’t know what’s ailing your plant, ask an expert.
Many gardeners get stumped when a favorite plant of theirs comes down with a strange “something”. Many of these gardeners know about UF/IFAS Extension and call their local horticulture and agriculture agents for assistance in figuring out what’s going on. However, even these experts are often stumped by what they see. Fortunately, the agents have another layer of experts to fall back on. In addition to the resources in Gainesville, we have the Plant Disease Diagnostic Clinic, located at the North Florida Research Center in Quincy. Plant pathologists here can help determine what fungus, bacteria, virus, or viroid may be the problem.
Plant pathologists are basically plant doctors. They use all sorts of sophisticated techniques to determine what is the cause of a particular plant problem, from growing out fungal spores to examining DNA. Not only do these plant doctors tell us what the ailment is, they also provide recommended cures, or control options. They are also doing research to prevent different diseases from taking hold in our area and reduce the impact on our local growers.
Plant pathologist at work!
At a recent workshop in Quincy, we learned that plant pathology researchers are working on a fungus that affects watermelons, virus and bacteria that can wipe out a farmer’s tomato crop, and a virus that could impact our local roses. Working as a team of scientists, they study these pathogens in the lab and conduct controlled field experiments to figure out which techniques are most effective. Some of this research is leading to different methods and/or products that can help growers and gardeners alike keep their fields and landscapes healthy.
So, if your plants have problems, please contact your local Extension Office. If they don’t know the answer, then the network of scientists, including plant pathologists, in the UF/IFAS Extension family can be called on for backup to provide you with the best possible answer.