by Daniel J. Leonard | Jul 22, 2021
If you’ve taken care of your yard properly from spring green-up to now (mid-July), you might think you can comfortably coast into the cool temperatures of fall without any problems. You would be mostly right, save for one extraordinarily tough weed that waits until the depths of summer to rear its troublesome head: Doveweed (Murdania nudiflora).
Doveweed seedlings just emerged on July 9, 2021. Photo courtesy of Daniel Leonard.
Doveweed is an insidious invader of Panhandle lawns. In the Panhandle, Doveweed germinates (sprouts) long after most other summer annual weeds, from late May-June when soil temperatures reach ~70°F. This allows it to sneakily avoid spring pre-emergent herbicide applications and even early summer post-emergent applications that target common weeds like Florida Pusley, Spurge species, and others. Doveweed also looks an awful lot like many of our common lawn turfgrasses, especially Centipede and St. Augustine Grass. It possesses thick, shiny, grass-like foliage and even grows in a spreading, low to the ground fashion. This mimicry causes many homeowners to not realize there is a problem until it’s too late. Once Doveweed is mature and displaying its characteristic purple flowers, it is very difficult to control. Finally, Doveweed is extremely tough and aggressive, particularly thriving in moist areas of the lawn. In these areas, Doveweed can easily outcompete the desirable turfgrass and, without intervention by you, will soon have the whole lawn to itself.
Controlling Doveweed is no easy task and requires a combination of practices to keep it out of your lawn. The first line of defense against any weed, Doveweed included, is through proper cultural practices. In turfgrass lawns, this means ensuring that you mow your lawn regularly and at the proper height (2.5” or so for Centipedegrass), keeping the lawn irrigated during droughty periods, fertilizing based on a soil test, etc. Being diligent in the above tasks will go a long way to ensuring that your turfgrass is healthy and better able to ward off a Doveweed invasion. However, even when homeowners maintain their turf perfectly, chemical herbicides are usually required to keep Doveweed at bay.
Doveweed patch in St. Augustine Sod.
While many commonly used homeowner herbicides are not effective on Doveweed, there are several quality options at your disposal.
- Doveweed is most easily controlled with preemergent herbicides, specifically one of the following: Atrazine, Pennant Magnum (S-metolachlor), Tower (dimethenamid), and Specticle (indaziflam). The issue with pre-emergents is that most folks shelve them after spring application in February or March. Since these products lose their efficacy after 4-6 weeks, Doveweed’s emergence in May is undeterred. To obtain control on Doveweed with these products, split the spring application and apply once in late Feb/early March and again in mid-late April.
- Doveweed can also be controlled by post-emergent herbicides after it is up and growing, though multiple applications may be required. The most effective formulations contain a combination of 2,4-D or Dicamba and other herbicides. While most of these products have at least fair efficacy on Doveweed, stronger, more expensive products like Celsius, Tribute Total and others provide better results.
- If Doveweed has already displaced turfgrass in large areas of your lawn, you may unfortunately be better off to make an application of a non-selective herbicide like glyphosate (Roundup), kill out the entire area of infestation and start over by resodding.
While Doveweed is a major problem in Panhandle lawns, it doesn’t have to be in yours! By keeping your turf healthy with proper cultural practices and making timely applications with effective herbicides, your lawn can be a Doveweed free zone! For assistance in Doveweed identification in your lawn, help choosing herbicides and calculating application rates, or any other horticultural information, contact us at the UF/IFAS Calhoun County Extension office! Happy Gardening!
by Sheila Dunning | Jul 15, 2021
Photo by Dr. Steve Johnson
Treefrog calls are often heard with each rain event. But, how about a “snoring raspy” call that begins after a day time light rain? That may be a male Cuban treefrog trying to attract the girls. Cuban treefrogs breed predominately in the spring and summer. Reproduction is largely stimulated by rainfall, especially warm summer rains such as those associated with tropical weather systems and intense thunderstorms.
Range of Cuban treefrogs
The Cuban treefrog, Osteopilus septentrionalis, was accidently introduced to Florida in the 1920’s as a stowaway in shipping crates from the Caribbean. Over the last hundred years, the invasive frog has managed to spread throughout Florida and the Southeastern U.S. by hitchhiking on ornamental plants, motorized vehicles, and boats. Though occasional cold winters have created temporary population setbacks, new generations of Cuban treefrogs continue to be reported in north Florida, including the Panhandle.
An invasive species is generally defined as a plant, animal or microbe that is found outside of its native range, where it negatively impacts the ecology, economy or quality of human life. Cuban treefrogs come out at night to feed on snails, millipedes, spiders and a vast array of insects. But, they are also predators of several Florida native frogs, lizards and snakes. Tadpoles of the invasive Cuban treefrog have been shown to inhibit the growth and development of native Southern toad and green treefrog tadpoles when all of the species are in the same water body. Additionally, a large female Cuban treefrog can lay over 10,000 eggs per season in very small amounts of water.
Panhandle citizens can help manage the invasive Cuban treefrog by learning to identify them and reduce their numbers. All treefrogs have expanded pads on the ends of their toes. Cuban treefrogs have exceptionally large toepads. They also have a “big eyed” appearance due to their oversized bulging eyes. Cuban treefrogs may exceed 6 inches in length, have warty-looking skin with possible blotches, bands or stripes, and vary greatly in color. However, they can be distinguished from other treefrogs. Cuban treefrogs have a yellowish wash where their front and rear legs are attached to their body. Juvenile Cuban treefrogs have red eyes and blue bones visible through the skin of their hind legs. The skin of the Cuban treefrog produces a sticky secretion that can cause a burning or itching sensation if it contacts the eyes or nose of certain individuals. It is recommended to wear gloves and wash your hands after handling Cuban treefrogs.
It is important to document the locations of Cuban treefrogs in the Panhandle. By placing short sections of PVC pipe in the ground around your home and garden will provide hiding places for treefrogs that enables you to monitor for Cuban treefrogs. Cut 10 foot sections of 1.5-inch-diameter PVC pipe into approximately three-foot-long sections and push them into the ground about 3-4 inches. To remove a frog from a pipe, place a clear sandwich bag over the top end, pull the pipe from the ground, and insert a dowel rod in the other end to scare the frog into the baggie. If you suspect you have seen one, take a picture and send it to Dr. Steve Johnson at tadpole@ufl.edu. Include your name, date, and location. Dr. Johnson can verify the identity. If it is a Cuban treefrog, upload the information by going to http://www.eddmaps.org/ and click the “Report Sightings” tab.
Once identified as a Cuban treefrog, it should be euthanized humanly. To do that, the Cuban treefrog in a plastic sandwich bag can be placed into the refrigerator for 3-4 hours then transferred to the freezer for an additional 24 hours. Alternatively, a 1-inch stripe benzocaine-containing ointment (like Orajel) to the frog’s back to chemically anesthetize it before placing it into a freezer. After freezing, remove the bagged frog from the freezer and dispose of in the trash. Ornamental ponds should also be monitored for Cuban treefrog egg masses especially after a heavy rain. The morning after a rain, use a small-mesh aquarium net to scoop out masses of eggs floating on the surface of the pond and simply discard them on the ground to dry out. Various objects that can collect water found throughout your yard need to be dumped out regularly to reduce breeding spots for both Cuban treefrogs and mosquitoes.
by Evan Anderson | Jun 24, 2021
There are lots of plant pests out there, and it can take a trained eye to tell which one is doing damage. Many of the insect pests that feed on crops and ornamentals have piercing-sucking mouthparts. These insects do not chew on leaves and leave holes behind; instead, they have a long stylus-like mouthpart they use like a straw to suck out plant juices. Over time this can weaken plants, cause irregular growth as damage builds up on new sprouts, introduce diseases to their hosts, and even cause mold to grow on leaves.
Because they drink so much fluid for their meals, many piercing-sucking insects exude a sugary liquid called honeydew. This liquid drops onto stems and leaves below which can leave them shiny and sticky. Eventually, the coating will grow a light greyish coating of sooty mold, which doesn’t do much harm to the plants itself but is a good indicator that you have an insect problem. You may also notice ants on your plants, working to harvest the honeydew for food. The ants don’t harm the plant, but following are some of the pests that do:
Aphids feeding on a plant stem.
A parasitic wasp emerging from a dead aphid.
Aphids – Found on a wide variety of plants, aphids are fat-bodied little insects that often focus on new, tender growth. Their color depends on the plant they’re feeding on, and they can breed explosively. A female aphid does not need to mate to produce offspring, so a one can produce a lot of children very quickly. Look closely and you might be able to see their cornicles, which look like little tailpipes; these can help identify these pests. Luckily, we have some help in controlling aphids, as they are often parasitized by wasps. If you see large, swollen, brown aphids present, you probably have some wasps working for you.
Ants tending some scale insects on a stem.
Scale Insects – Sometimes appearing to just be a bump on a stem or leaf, scale insects don’t move once they pick a plant to live on. Prolific producers of honeydew, some species grow a waxy shell which can protect them and make them difficult to deal with.
A mealybug.
Mealybugs – If you spy something white and fluffy living on stems or leaves, you might have mealybugs. Soft-bodied insects that are related to scales, they don’t move much. They feed on a wide range of host plants, but can effectively be controlled with a variety of methods once they’re found.
Whiteflies on the underside of a leaf.
Whiteflies – Not true flies, they are truly white in color. Tiny little members of the order Hemiptera (the same order that includes, aphids, scales, and mealybugs), they hang around the undersides of leaves. They enjoy warm weather and can become a problem in greenhouses. They are a bit more difficult to control than some of the other pests listed here.
A psyllid nymph hiding in its waxy coating.
Psyllids and planthoppers – Small jumping insects that affect a variety of plant species, some are responsible for transmitting important plant diseases. Pierce’s disease of grapes and citrus greening, for example, are both vectored by these critters. Young nymphs sometimes secrete a waxy coating which may make them look similar to mealybugs.
A tiny two-spotted spider mite.
Spider Mites – Not an insect but an arachnid, spider mites love hot, dry weather. Almost microscopic in size, the damage they do to leaves is often the first sign that they are present. Looking closely, one might notice tiny webbing where the mites live, or even the mites themselves on the undersides of leaves and on stems.
Many of these pests can be treated with a combination of methods. A sharp jet of water can dislodge some, hand removal can reduce populations even more, and products such as insecticidal soap or horticultural oils can finish them off. Insecticidal soaps are best used on soft-bodied insects such as aphids or mealybugs, while oils such as neem can help suffocate hard scales. Use products such as horticultural oil in the evening during hot weather to avoid damaging plant tissues with intense sunlight. Thorough coverage is important, as these products only control the pests they contact.
For more information on controlling insects, see our EDIS publications, such as Insect Management in the Home Garden or Landscape Integrated Pest Management.
by Evan Anderson | May 20, 2021
A number of landowners in our region have been noticing a number of caterpillars coming down from the treetops. Sometimes appearing in vast numbers, the forest tent caterpillar has been found throughout Florida and the United States. Several years of heavy infestation occurred in Central Florida more than a decade ago, but populations are usually not high enough to cause significant damage to trees.
A forest tent caterpillar. – Photo courtesy of Shoal Sanctuary Nature Preserve.
The forest tent caterpillar is the larval stage of a somewhat nondescript brown moth. The moths lay their egg masses on twigs, and the eggs hatch in the spring. Caterpillars feed on a variety of tree species, but seem to prefer oak and gum trees. They spend anywhere from two to six weeks eating. When they are nearing maturity, they can become a problem for humans who do not appreciate the many droppings they produce, or their habit of descending from the trees to find places to spin their cocoons. They are sometimes attracted to lights or the walls of buildings, where they congregate in search of a place to pupate. They are not harmful to people, however.
A forest tent caterpillar egg mass. – Photo courtesy of Jeffrey Lotz, Division of Plant Industry
Particularly cold winters may help decrease populations of these caterpillars. Inclement weather or high temperatures may do the same in the summer, and natural predators often help to control populations when present as well. Controlling forest tent caterpillars is most often unnecessary even when there are large numbers of them. It may help to avoid parking cars under large infestations or to turn off outdoor lighting that might attract them at night. If they wander indoors, check screens and window seals to be sure there are no gaps for them to enter.
If these or other caterpillars become such a nuisance that control measures must be considered, consider using a product such as Bacillus thuringiensis, or Bt, which specifically affects caterpillars and not other beneficial insects. Keep affected trees healthy with proper fertilization and watering, and even a defoliated tree will probably recover from any damage these insects cause. For more information, see our EDIS publication on the Forest Tent Caterpillar or contact your local Extension office.
-Evan Anderson, Walton County Horticulture Agent.
by Matt Lollar | Apr 1, 2021
If you’ve been raking leaves recently, you’ve probably noticed little green worms hanging from the trees. They seem to be in abundance this year and can be found crawling on driveways, just hanging around, and maybe even feeding on oak tree leaves.
These green worms that are all over the yard are oak leafrollers (Archips semiferanus) or oak leaftiers (Croesia semipurpurana). Some people may refer to them as inchworms, however a number of different caterpillars can go by that name. Leafrollers and leaftiers range in length from 1/4″ to 1″. The adult form of these insects is a 1/2″ long moth. The oak leafroller moth is mottled tan and brown and the oak leaftier moth is yellow with brown markings.
An oak leafroller caterpillar crawling on a leaf. Photo Credit: Blair Fannin, Texas A&M University
In May, the adults of both species lay their eggs in the twigs and leaf buds of a number of tree species. The eggs don’t hatch until March of the following year. When the caterpillars emerge, they feed on the newly forming leaves and flowers of oak, hackberry, pecan and walnut trees. If they are disturbed, they will stop feeding and hang from a strand of silk. Oak leafroller caterpillars pupate in tree branches, while oak leaftier caterpillars drop to the ground and pupate in leaf litter. Adult moths emerge in one to two weeks.
A leafroller moth with wings spread. Photo Credit: U.S. National Museum
The oak leafrollers and oak leaftiers don’t really do enough damage to be considered pests, but they are a bit of a nuisance. Thankfully, birds and parasitic wasps will eat and kill the majority of the population. For in-depth information on most of the interesting insects in your yard, please visit the UF/IFAS Featured Creatures Website.
by Larry Williams | Mar 25, 2021
As a boy in a small town in Georgia we had a St. Augustinegrass lawn. My dad started the lawn before I was born. That lawn was still doing fine when I left for college at age seventeen. I don’t remember weeds in the lawn during summer months. I do fondly remember winter “weeds” in that lawn.
To see clumps of winter annuals in our yard and in neighbors’ yards was a natural part of the transition from winter to spring. They added interest to what
Blue Easter egg hidden in chickweed. Photo credit: Larry Williams
would have been a plain palette of green. It was expected to see henbit with its square stiff stems holding up a display of small pinkish purple flowers in late winter and early spring. A clump of henbit was a great place to hide an Easter egg, especially a pink or purple one.
Wild geranium, another common winter annual, offered another good hiding place for Easter eggs with its pink to purple flowers. Large clumps of annual chickweed would nicely hide whole eggs. Green colored eggs would blend with chickweed’s green leaves.
Pink Easter egg hidden in crimson clover & hop clover mix. Photo credit: Larry Williams
Crimson clover with its reddish flowers, hop clover and black medic with their bright yellow flowers were good hiding places for Easter eggs. Plus clovers add nitrogen back to our soils.
I never remember my dad using any weed killer, he rarely watered. The lawn was healthy and thick enough to be a deterrent to summer weeds. But during fall and winter as the lawn would naturally thin and go dormant, winter annual weeds would run their course.
I’ve heard that the sense of smell provides our strongest memories. I remember the first mowing of the season with the clean smell of chlorophyll in the spring air. It was refreshing. Once mowed and as the heat took its toll, by late April or mid-May, these winter annual weeds were gone. What was left was a green lawn to help cool the landscape as the weather warmed. The lawn was mowed high as St. Augustine should be, played on and typically not worried with.
Most people have winter weeds in their lawns that let us know spring is near. Perhaps we worry too much with these seasonal, temporary plants that may have wrongly been labeled as weeds. Besides, how long have we been doing battle with these weeds and they are still here. Most lawns have countless numbers of winter annual seeds awaiting the cooler temperatures and shorter days of early winter to begin yet another generation. By May they are gone.
