Fall Weed Control in Pastures

Fall Weed Control in Pastures

Fall is not generally the right time to control many pasture weeds.  However, some perennial weeds are effectively controlled by fall herbicide applications.  Fall is a good time to treat for weeds such as cogongrass, blackberries, dewberries, biennial thistles, and Chinese Tallow trees.


cogongrass flowering

Cogongrass flowering

Cogongrass is an invasive warm season perennial grass.  It spreads by rhizomes and seed in north Florida.  It can quickly spread from roadsides or forest areas into pastures.  Established areas of cogongrass can have massive root systems making them difficult to control.  Eradication of cogongrass infestations often take 3 or more years of twice a year treatments.  Currently, only products with the active ingredients glyphosate and imazapyr are effective against cogongrass.  Spring and fall treatments of either glyphosate, imazapyr or a combination of the two should be applied until the infestation is eradicated. Both of these herbicides are non-selective and will likely result in bare ground in treated areas.  These areas are not going to produce adequate forage for animals so owners should consider this in their grazing management plan.  For more information on cogongrass and treatment plans, please read the following UF/IFAS publication: Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands

Blackberries and Dewberries

blackberry plants

Blackberries grow upright and have hard, tough thorns.

Blackberry and dewberry control in pastures is difficult to achieve.  The first step is identification of the plant.  Blackberries grow upright while dewberries have a low vine-like growth habit.  Dewberries have slender thorns and red hairs on the stem while blackberries have hard, tough thorns and no hairs.  Blackberries grow up to 3-6 feet tall, however, dewberries rarely reach over 2 feet in height.  Also, the seeds of dewberries are harder and much larger than that of blackberries.

dewberry plants

Dewberries have slender thorns and red hairs on the stem and are low growing and somewhat vine-like.

For blackberries, effective broad spectrum herbicides include:  Pasturegard HL (triclopyr + fluroxypyr), or Remedy Ultra (triclopyr ester).  You can either apply these herbicides in the spring when the plants are blooming, or in the fall.  Fall applications are more effective.

For dewberries, use Pasturegard HL (2pt/acre) but only expect 60-70% control.

Remember to wait at least 6 weeks after applying the herbicide before mowing.  For more information on blackberries and dewberries in pastures, please read the following UF/IFAS publication:  Blackberry and Dewberry: Biology and Control

Biennial Thistles

first year thistle plant

First year thistles, in the rosette stage, are easiest to control.

Most thistles in Florida are biennial, meaning they live for two years.  Thistles begin as a rosette and remain in this stage for the first year.  In year two, the thistle sends up a stalk and flowers, produces seeds and dies.  Thistles bolt (send up the stalk) January through July and flower from April through August.  Each plant can produce up to 4,000 seeds. The key to controlling thistles is to keep the plant from flowering and producing seeds.

Thistles in the rosette stage are the most susceptible to herbicides but are hardest to see in the field since they lay flat on the ground.  Once the thistles bolt, they are harder to kill with herbicides.  Effective herbicides for thistles during the rosette stage include 2,4-D, triclopyr, GrazonNext HL, PastureGard HL and Weedmaster.  For more information on thistle control in pastures, please read the following UF/IFAS publication:  Thistle Control in Pastures

Chinese Tallow Trees (Popcorn Trees)

chinese tallow seedling

Chinese Tallow seedlings can be treated by foliar applications of triclopyr ester.

Chinese Tallow, also known as the Popcorn Tree, was introduced in the US over 200 years ago.  They are prolific invaders of natural areas, pastures, wetlands, and yards.  Mature trees can be cut down with a chain saw and the stump promptly treated with an herbicide with the active ingredient, triclopyr amine.  You should try to make the final cut as low to the ground as possible.  You can use a paint brush to apply the herbicide to the stump.  A basal bark application of triclopyr ester plus a penetrant oil can be used on smaller trees.  Treat the trunk to a height of 12 to 15 inches from the ground, thoroughly wetting it on all sides with the herbicide mixture.  Basal bark treatments are only effective on saplings and seedlings less than 6 inches in stem diameter.  Sometimes suckers may sprout from remaining roots.  A foliar application can be used on these sprouts from July to October, before onset of fall color. For more information on Chinese Tallow, please read the following UF/IFAS publication:  Natural Area Weeds: Chinese Tallow

For more information on pasture weed control, use the following publication link:  Weed Management in Pastures and Rangeland

Equine Infectious Anemia is Still a Concern for Horse Owners

Equine Infectious Anemia is Still a Concern for Horse Owners

Horses at the University of Florida Horse Teaching Unit. UF/IFAS Photo by Tyler Jones.

Sometimes we can get complacent and forget why we do things. A Coggins test in horses is one of those things.  We know that it is a requirement in Florida to have a current negative Coggins test (within the last 12 months) in order to:

  • Move horses within the state,
  • Move horses out of the state,
  • Change ownership of the horse,
  • Breed horses,
  • Congregate horses for the purpose of shows, exhibits, sales/auctions, trail rides, rodeos and even boarding.

Normally, proof of negative Coggins test is in the form of a paper with information about the owner, horse and lab performing the test. Cards (negative EIA test verification cards) are available for an additional fee.  These cards are more convenient for those who travel often with their horses.

But why do we need a negative Coggins test every 12 months?

The Coggins test screens horses for Equine Infectious Anemia (EIA), a viral disease that has no vaccine and no treatment. A veterinarian must collect the blood sample and send it to a state and federally approved lab for testing.  The US started using this test in 1972 and has significantly reduced the number of new cases since then.  The EIA virus is transmitted by large biting flies such as horseflies and deerflies.  Contaminated needles and equipment can also spread this virus.  Horses with EIA can show clinical signs such as fever, weight loss, yellowing of skin, anemia, swelling of limbs and weakness.  Some horses with EIA show no signs of infection, but can still transmit the virus to healthy horses.

Horses that test positive for EIA are either euthanized or segregated from negative horses. USDA has set forth Uniform Methods and Rules for detecting, controlling and preventing the spread of EIA in the US. This is the minimum standard for states to follow.  Florida rules exceed these minimum standards since we are an historic “hot zone” state.

In 2017, 108,388 Coggins tests were performed in Florida with 2 horses testing positive. So far in 2018, one positive horse has been reported in March in Hardee County. Currently in the US less than 0.01% of horses tested are positive for EIA.  In 1972, when testing was implemented 4% of horses tested were positive.  If we get complacent and ignore EIA, since it is no longer very prevalent, we will see an increase in cases around the US.  Since there is no vaccine and no treatment for this disease, which can be fatal, testing is our best defense against this virus.


Using Solar Energy to Pump Water for Livestock

Using Solar Energy to Pump Water for Livestock

Photovoltaic panel providing solar power to a remote well used for watering livestock.
Photo credit: Jennifer Bearden

Sometimes the cost of running overhead power lines to power remote pumps is cost prohibitive on large acreages.  This causes farmers and ranchers to look for alternative energy sources.  In Florida, a great energy source is solar energy.

There are many advantages to using solar energy to pump water for livestock.  It is a definite cost saving to the rancher.  The initial cost of set up may be much less expensive than running overhead lines, plus the cost of running the system is very low.  Using solar power, remote locations can now have a well and power to run the well.  Maintenance on these systems is very low.  The lifespan of solar panels is over 20 years now and many companies warranty them for that length of time.

Having access to water in remote locations allows the rancher to keep livestock out of surface waters.  This is not only good for the environment but has also been proven to be good for the health of the herd.

The system pumps water only when the solar panels gather sunlight.  When the sun is not shining, the pump is not pumping.  That is one disadvantage of the system.  However, if you set up your system to include a DC-to-AC inverter, you can use a generator to run the system during extended periods of cloudiness.

Components of the system include a well, a submersible pump with DC motor, a controller, a photovoltaic array (solar panels), and a water storage tank.  A DC-to-AC inverter may also be installed as insurance against cloudy days.

There are many things to consider when designing your system such as daily water requirement, storage tank capacity, pumping requirements, hydraulic workload, pump and flow rate and photovoltaic determination.  Each system is different because each water well is different.  Differences in depth of the well, width of pipe, elevation and height of the water storage tank makes it difficult to have cookie cutter specifications.  This process involves math and physics.  Many ranchers will want to work with experts to determine these values in order to design the system properly.

The USDA NRCS has a cost-share program to help offset the cost of setting up a solar pumping system for livestock.  They are also a great resource when designing the system.  Your local county extension agent can also help you find resources for designing your system.

Please click on the video below for a first hand look at one of these systems in operation on a local Walton County ranch.


For more information on this topic, please consult the following resources: 

Co-authored by Mike Goodchild, Walton County Extension Director


Sunn Hemp for Forage or Wildlife Food Plots

Sunn Hemp for Forage or Wildlife Food Plots

Sunn hemp pasture in Walton County. Photo Credit: Jennifer Bearden

Sunn hemp is a fast growing, warm season, annual legume.  It grows 6-7 feet tall.  Sunn hemp can tolerate a wide range of soil pH (5.0-8.4).  It is native to India and Pakistan.  The University of Hawaii and USDA NRCS, together, released the variety called “Tropic Sun” in 1982.  This variety only makes seed during periods of short day length and a certain range of temperatures.  These factors limited seed production.  Recently, however, Auburn University released AU Golden and AU Darbin varieties that are able to produce seeds in more temperate climates.  Since sunn hemp is a legume, it fixes more than 120lbs of nitrogen from the environment per acre, per season.  It can yield 3,000 to 10,000lbs of forage per acre.  It can be grown in a wide range of soil types, but is most productive in more fertile soils.  Sunn hemp has traditionally been utilized as a cover crop, but has recently been evaluated as a forage for livestock as well for wildlife food plots.

The advantages of using sunn hemp as a cover crop are the large amount of biomass produced per acre, nitrogen fixation, nematode suppression, and weed suppression.  Because it can grow in a wide range of soil types and pH levels, and because of its drought tolerance, hunters have tried it for wildlife food plots.  Research has shown that Sunn Hemp is an acquired taste, and that livestock and wildlife need time to become accustomed to it, but the nutrient quality of the leaves is very high with crude protein (CP) ranging from 25-30%.

Sunn hemp is an interesting option for livestock warm season annual grazing.  Plant sunn hemp once soil temperatures have reached 65°F.  Use a seeding rate of 25-30lb per acre and planting depth of 1/4” to 1”.  Don’t forget the cowpea type inoculant.  Because this is a legume crop that fixes its own nitrogen (N), N fertilization is not required.  Soil test for pH, phosphorus and potassium prior to planting, and apply the recommended nutrients based on the soil test results.

Grazing management is very important for Sunn Hemp. The goal is to keep the plants in a vegetative growth stage with a high percentage of leaves compared to stalks.  The leaves are 25-30% CP with TDN of 65-71%.   The stems are much lower quality (8-10% CP and 22% TDN).  Grazing and forage management should focus on maximizing leaf-to-stem ratio.  Start grazing approximately 45 days after planting when the sunn hemp reaches 1.5-3 feet tall. If you wait too long, sunn hemp can reach a height of over 6′ and livestock will break off the plants and prevent regrowth.  Stop grazing when stubble is 12-18″ to allow regrowth.  Overgrazing or mowing below 12″ can kill the plant and prevent regrowth.  Because of its high quality, sunn hemp works well using limit grazing (1-3 hours/day) to compliment traditional perennial pastures.

Sunn Hemp is an annual legume that is not related to industrial hemp or marijuana.  It is actually in the Crotalaria family, but unlike other species in this plant family that are toxic, sunn hemp contains much lower levels of alkaloid compounds.  Sunn hemp seeds do contain small amounts of toxic alkaloids, so seeds should not be fed in livestock diets.  Small amounts of seeds consumed while grazing are not enough to cause acute toxicity.  The leaves and stems are not toxic to livestock.


For more information on using sunn hemp as a forage, use the following link to a recently published Alabama Extension fact sheet:

Grazing Sunn Hemp


Diagnosing the Cause of Yellowing Peanut Fields

Diagnosing the Cause of Yellowing Peanut Fields

It happens every year. You cruise peanut fields and see spots of yellowing in a field.  The million dollar question is, “What is causing this yellowing?”  Unfortunately, there are many answers to this question. Problems that cause yellowing in peanuts can Include:

  • manganese deficiency

  • poor inoculation

  • standing water or drought

  • zinc toxicity

  • sulfur deficiency

  • herbicide damage

The best way to positively diagnose these problems is to take plant tissue and soil samples.  Two recent fields, described below, presented yellowing symptoms and are a good example of why it is best to positively diagnose problems through testing rather than guessing.

Field 1.  Peanut field with very slight yellowing. Photo by Jennifer Bearden

Field 1

The first field had slight yellowing and was pretty uniform across the field. Boron and Manganese had just been applied to the field because it is customary to apply these two micronutrients to fields in our area.  Plant tissue tests revealed low levels of phosphorus and magnesium, and high levels of boron and manganese.  Low magnesium levels can cause yellowing.  A soil sample was not performed as this field greened up without any further issues after addition of magnesium.

Field 2.  Characteristic stem and taproot splitting due to Zinc toxicity. Photo by Jennifer Bearden

Field 2

The second field also was yellowing, but there were areas that were worse than others. One area had telltale zinc toxicity issues with stem splitting.  This area was near a pecan tree.  It is common to see zinc toxicity near pecan trees since pecan trees are routinely fertilized with zinc.  A plant tissue test and soil test were performed in another problem area of the field.  The soil test results revealed toxic levels of zinc and manganese, and low pH.  The pH level kept the manganese from affecting the plant, but it was not high enough to protect the plant from zinc toxicity.  Management for this portion of the field in the future should include liming the field to raise the pH to at least 5.9 to protect the peanut plants from zinc toxicity.

A side note on peanut fertilization: potassium and magnesium fertilization should occur prior to, or early on in the season.  Potassium and magnesium are cations and can interfere with the uptake of calcium if they are present in excess quantities at the pegging zone at the beginning pod stage.  Also remember that some nutrients can be toxic in excessive quantities, so care should be taken to only apply what the crop needs.  Soil testing and plant tissue testing takes the guesswork out of peanut fertilization.

For more information on peanut nutrient management, use the following links: