by Pat Williams | Sep 9, 2021
As homeowners, we do value our trees and no one wants to lose a shade tree especially on the house’s south side in Florida. On a recent site visit, a hickory tree had multiple concerns. Upon closer inspection, the tree had a bacterial infection about 30” off the ground with a smelly, black-brown ooze seeping forth. The leaf canopy was riddled with beetle holes and leaf margins were chewed by caterpillars. When leaves were viewed under the microscope, thrips (insects) and spider mites were found running around. The biggest homeowner cosmetic concern arose from hickory anthracnose (fungus) and upon closer inspection found the leaves to have hickory midge fly galls. The obvious question is should the tree come down? I’ll have you read the whole article before giving you the answer.
Each hickory gall is approximately 3/16″ wide.
Hickory anthracnose or leaf spot as seen in the banner photo is caused by a fungal infection during the wet summer months in Florida. The homeowner can usually recognize the disease by the large reddish brown spots on the upper leaf surface (sending a sample to the NFREC Plant Pathology Lab will confirm the diagnosis) and brownish spots with no formal shape on the bottom. Be sure to rake and remove all leaves to prevent your disease from overwintering close to the tree thus reducing infection next year.
A hickory gall has been cut in half to show the leaf tissue.
The fungus can be lessened by good cultural practices and appropriate fungicidal applications. Please remember it is best left to professionals when spraying a large tree. This alone is not cause to remove your tree.
Hickory gall is caused by the hickory midge fly, an insect that lays eggs in the leaf tissue. The plant responds by building up tissue around each egg almost like the oyster when forming a pearl.
As the gall tissue grows, eggs hatch and larva start to feed on this tissue. The larva will continue to
The larva has eaten all soft material inside the gall and is ready to pupate.
feed until it is ready to pupate within the gall. After forming a pupa, the midge fly will eventually emerge as an adult and females will continue to lay eggs on other leaves. The galls are more of a cosmetic damage and because your hickory leaves will fall from the tree as winter comes, the galls will normally not cause enough damage to worry about each year. Once again good cultural practices and disposal of each year’s leaves will reduce the gall numbers next year.
In a large tree with many leaves, foliar feeding by beetles and caterpillars do cause damage though the leaves will still produce enough food (photosynthesis) to keep the tree alive. Most of us never climb our trees to look at leaves to see the small insects/mites and there are more than enough leaves to maintain tree health.
The biggest concern during my site visit was their tree’s bacterial infection. A knife blade was pushed into the wound area and went in less than 1/4″. The homeowner was instructed to look at bactericide applications. In the end, this hickory tree with so many problems is still shading the home and helping cool the house. It is still giving refuge to wildlife and beneficial insects. When in doubt give our trees the benefit and keep them in place. Remember your local Extension agent is set up to make site visits and saving a tree is time well spent.
by Matt Lollar | Sep 1, 2021
Last week I was trimming shrubs around my house and I had the wild idea to pull up a couple yaupon holly saplings around the base of a live oak tree…without looking. As I was pulling up one of the saplings I felt a piercing sting on my ankle. I yelled some obscenities and ran away as quickly as I could, but it was no use. By the time I got far enough away, I had been stung eleven times and I still had a few yellowjackets flying around in my shorts.
Southern yellowjackets create underground colonies that can hold over 2,000 yellowjackets. Photo Credit: UF/IFAS
Two species of yellowjackets can be found in Florida along with a similar species known as the baldfaced hornet. The eastern yellowjacket (Vespula maculifrons) is found in eastern North America and the southern yellowjacket (Vespula squamosa) is found in the eastern United States, Mexico, and Central America.
Southern yellowjacket, Vespula squamosa (Drury), nest dug from ground.
Credit: Gerald J. Lenhard; http://www.insectimages.org/
Yellowjacket colonies are started in the spring by a single queen that mated in the fall and overwintered. Yellowjacket nests consist of a series of horizontal combs that may be above ground, underground, or both. The queen builds the initial nest and forages for food on her own. Her offspring then assume all jobs except for laying eggs. In the fall, larger cells are built for a new batch of queens. The new queens then emerge, mate, and seek shelter for the winter. The old queen dies and the remaining colony breaks down.
Yellowjackets aren’t all bad, they provide a great service to our gardens and landscapes by attacking a number of insects that are pests to our crops. However, the moral of this story is to always be aware of what is lurking under your feet and above your head. And maybe yaupon hollies shouldn’t be messed with regardless of their native invasiveness. Nests are less active at night, but any disturbance will trigger an attack. However, it is best to leave nest removal to professionals.
by Mary Salinas | Aug 20, 2021
On August 12, 2021, our panel answered questions on a wide variety of landscape topics. Maybe you are asking the same questions, so read on!
Ideas on choosing plants
What are some perennials that can be planted this late in the summer but will still bloom through the cooler months into fall?
Duranta erecta ‘Sapphire Showers’ or ‘Gold Mound’, firespike, Senna bicapsularis, shrimp plant, lion’s ear
Where can native plants be obtained?
Dune sunflower, Helianthus debilis. Photo credit: Mary Salinas UF/IFAS Extension.
Gardening Solutions: Florida Native Plants – see link to FANN: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/native-plants.html
What are some evergreen groundcover options for our area?
Mondo grass, Japanese plum yew, shore juniper, ajuga, ferns such as autumn fern.
What are some ideas for partial morning sun butterfly attracting tall flowers to plant now?
Milkweed, salt and pepper plant, swamp sunflower, dune sunflower, ironweed, porterweed, and salt bush.
I’m interested in moving away from a monoculture lawn. What are some suggestions for alternatives?
Perennial peanut, powderpuff mimosa, and frogfruit.
We are new to Florida and have questions about everything in our landscape.
Florida-Friendly-Landscaping TM Program and FFL Web Apps: https://ffl.ifas.ufl.edu/
https://ffl.ifas.ufl.edu/resources/apps/
UF IFAS Gardening Solutions: https://gardeningsolutions.ifas.ufl.edu/
What are some of the top trends in landscaping today?
Houseplants, edible gardens, native plants, food forests, attracting wildlife, container gardening, and zoysiagrass lawns
Edibles
Artwork broccoli is a variety that produces small heads. Photo credit: Mary Salinas UF/IFAS Extension.
What vegetables are suitable for fall/winter gardening?
Cool Season Vegetables: https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/cool-season-vegetables.html
North Florida Gardening Calendar: https://edis.ifas.ufl.edu/publication/EP451%20%20%20
Florida Vegetable Gardening Guide: https://edis.ifas.ufl.edu/publication/vh021
How can I add herbs to my landscape?
Herbs in the Florida Garden: https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/herbs.html
My figs are green and hard. When do they ripen?
Why Won’t My Figs Ripen: https://www.lsuagcenter.com/profiles/rbogren/articles/page1597952870939
What is best soil for raised bed vegetable gardens?
Gardening in Raised Beds: https://edis.ifas.ufl.edu/publication/EP472
And there are always questions about weeds
How can I eradicate cogongrass?
Chamber bitter is a troublesome warm season weed in our region. Photo credit: Brantlee Spakes Richter, University of Florida, Bugwood.org
Cogongrass: https://edis.ifas.ufl.edu/publication/WG202
Is it okay to use cardboard for weed control?
The Cardboard Controversy: https://gardenprofessors.com/the-cardboard-controversy/
What is the best way to control weeds in grass and landscape beds?
Weed Management Guide for Florida Lawns: https://edis.ifas.ufl.edu/publication/EP141
Improving Weed Control in Landscape Planting Beds: https://edis.ifas.ufl.edu/pdf/EP/EP52300.pdf
Landscape practices
Can ground water be brackish and stunt plants?
Reclaimed Water Use in the Landscape: https://edis.ifas.ufl.edu/publication/ss545
How can I prevent erosion from rainwater runoff?
Stormwater Runoff Control – NRCS: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/water/?cid=nrcs144p2_027171
Rain Gardens: https://gardeningsolutions.ifas.ufl.edu/design/types-of-gardens/rain-gardens.html
And https://gardeningsolutions.ifas.ufl.edu/pdf/articles/rain-garden-manual-hillsborough.pdf
What is the best time of the year to propagate flowering trees in zone 8B?
Landscape Plant Propagation Information Page – UF/IFAS Env. Hort: https://hort.ifas.ufl.edu/database/lppi/
Which type of mulch works best on slopes greater than 3 percent?
Landscape Mulches: How Quickly do they Settle?: https://edis.ifas.ufl.edu/publication/FR052
When should bulbs be fertilized?
Bulbs and More – UI Extension: https://web.extension.illinois.edu/bulbs/planting.cfm
Should I cut the spent blooms of agapanthus?
Agapanthus, extending the bloom time: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/agapanthus.html
http://blogs.ifas.ufl.edu/wakullaco/2020/10/07/extending-bloom-time/
Plant questions
Monarch caterpillar munching on our native sandhill milkweed, Asclepias humistrata. Photo credit: Mary Salinas, UF IFAS Extension.
I planted native milkweed and have many monarch caterpillars. Should I protect them or leave them in nature?
It’s best to leave them in place. Featured Creatures: Monarch Butterfly: https://edis.ifas.ufl.edu/pdf/IN/IN780/IN780-Dxyup8sjiv.pdf
How does Vinca (periwinkle) do in direct sun? Will it make it through one of our panhandle summers? Can I plant in late August?
Periwinkles and No more fail with Cora series: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/periwinkles.html#:~:text=Plant%20your%20periwinkles%20where%20they,rot%20if%20irrigated%20too%20frequently.
Insect and disease pests
What to do if you get termites in your raised bed?
The Facts About Termites and Mulch: https://edis.ifas.ufl.edu/publication/IN651
How to combat fungus?
Guidelines for ID and Management of Plant Disease Problems: https://edis.ifas.ufl.edu/publication/mg442
Are there preventative measures to prevent diseases when the humidity is very high and it is hot?
Fungi in Your Landscape by Maxine Hunter: http://blogs.ifas.ufl.edu/marionco/2020/01/16/fungi-in-your-landscape/
If you missed an episode, check out our playlist on YouTube https://www.youtube.com/watch?v=bp0HfdEkIQw&list=PLhgoAzWbtRXImdFE8Jdt0jsAOd-XldNCd
by Mary Salinas | Aug 18, 2021
For those of you who tuned into the July 29 edition of Gardening in the Panhandle LIVE, beneficial insects was the topic of the day. Here are links to the publications our panelists talked about.
Mantid. Photo credit: David Cappaert, Bugwood.org.
How do I identify the kind of insect I have?
Recognizing beneficial bugs: Natural Enemies Gallery from UC Davis http://ipm.ucanr.edu/natural-enemies/
How to distinguish the predatory stink bug from the ones that harm our crops: https://entomology.ces.ncsu.edu/wp-content/uploads/2014/01/FL-pred.jpg
How to tell difference in stink bugs and leaf footed insects. Are both harmful? UF/IFAS Featured Creatures: leaffooted bug – Leptoglossus phyllopus (Linnaeus) (ufl.edu)
How can I tell bad beetles from good ones? Helpful, Harmful, Harmless Identification Guide is one resource available: http://ifasbooks.ifas.ufl.edu/p-153-helpful-harmful-harmless.aspx
How can we encourage beneficial insects?
How can we encourage the beneficial insect species?
- Plant more flowers attract pollinators that also feed on insects.
- Diversity of plants in the landscape.
- Use softer or more selective pesticides to minimize damage to beneficials.
Is it helpful to order beneficial insects such as lady bugs? Encouraging Beneficial Insects in Your Garden OSU: https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/pnw550.pdf
How effective is buying predatory insects to release in your greenhouse? Natural Enemies and Biological Control: https://edis.ifas.ufl.edu/publication/IN120
Can I buy beneficial insects to start breeding in my garden? Natural Enemy Releases for Biological Control of Crop Pests: https://www2.ipm.ucanr.edu/agriculture/natural-enemy-releases-for-biological-control-of-crop-pests/
What benefit would result by planting city right-of-ways with native wild flowers? https://edis.ifas.ufl.edu/publication/in1316; https://adamgdale.files.wordpress.com/2020/03/gcm_feb2020.pdf
Can an individual gardener sustain an ecosystem for beneficial insects? Penn State Article on beneficial insects that mentions some flowering plants that help support predators and parasitoids: https://extension.psu.edu/attracting-beneficial-insects
Specific Insects
How do I get rid of mole crickets? UF/IFAS Mole Crickets: https://edis.ifas.ufl.edu/entity/topic/mole_crickets
Are wasps really beneficial? Beneficial Insects: Predators!: https://sfyl.ifas.ufl.edu/sarasota/gardening-and-landscaping/horticulture-commercial/integrated-pest-management/beneficial-insects/
Is a dish soap solution effective against wasps? Soaps, Detergents, and Pest Management: https://gardeningsolutions.ifas.ufl.edu/care/pests-and-diseases/pests/management/soaps-detergents-and-pest-management.html
How to control leaf footed bugs? Handpick them, attract beneficials, create diverse plantings in landscape, accept some damage, and control them when in the juvenile stage.
Can you tell me about praying mantids? Praying Mantids: https://entomology.ca.uky.edu/files/efpdf2/ef418.pdf
Are there any beneficial insects that keep mosquito populations down? Dragonfly larvae in water, mosquitofish
What are the little insects that hop out of centipede grass? Are they beneficial?
Spittlebugs and your lawn: https://nwdistrict.ifas.ufl.edu/hort/2020/05/27/spittlebugs-and-your-lawn/
How to stop Eastern Black Swallowtail Butterflies laying eggs on parsley – the hatched caterpillars eat it all. Plant extra or put a screen over plant.
Extra fun video!
Take a look at this video of parasitic wasp attacking aphids: Parasitic Wasps | National Geographic – YouTube
by Mark Tancig | Jul 29, 2021
Now that we’re getting plenty of rain and the temperatures are nice and toasty, our nemesis to enjoying the outdoors is back in full force. Yes, I’m talking mosquitoes, the reason for inventing window screens! If you’re gardening outside these days, you’ve probably been annoyed by one of the many mosquito species that occur in our area. Many of these mosquitoes are native species that play an important role in the food chain, feeding many aquatic and terrestrial wildlife, but some of them, like the daytime biting Asian tiger mosquito, are invasive species that were accidentally introduced. While mosquitoes are an important food source to more charismatic critters, they are annoying and can spread disease, and so we can benefit by reducing their presence.
The Asian tiger mosquito, another annoying invasive species. Photo credit: Susan Ellis, Bugwood.org.
In addition to the age-old advice of draining any standing water, there are other control methods that can be very effective at reducing the mosquito population. One of the most effective and least-toxic options is the use of Bti products. These products come in granular or “donut” forms with the smaller granules being best for various uses around the home and the dunks/donuts for larger areas of standing water like ponds. These Bti products are considered a type of biological control since it is a species of bacteria, Bacillus thuringiensis israelensis to be precise, that causes mosquito, blackfly, and fungus gnat larvae to perish as they wiggle around and grow into their pupal stage. Because it only affects a narrow range of species, it is considered a selective pesticide that does not cause harm to non-target species, such as bees, birds, butterflies, frogs, lizards, and other desirable garden visitors. Bti can be sprinkled into rain barrels, bird baths, bromeliads, gutters, and other places where water may stand more than 5-7 days, the amount of time needed for mosquito eggs to develop into adults.
Bti granules prevent mosquito larvae from becoming biting adults. Photo by: Mark Tancig, UF/IFAS.
If considering other methods of mosquito control, such as the use of foggers, keep in mind that many of the pesticides used to control adult mosquitoes are not selective products and can kill the pollinators you may be trying to invite to your garden. Additionally, planting citronella plants, eating copious amounts of garlic, wearing repellent bracelets, or using ultra-sonic devices or cell phone apps has not been shown to repel mosquitoes so stick to what is known to work.
For a more enjoyable mosquito season, keep the window screens tight, wear long pants and sleeves and use appropriate repellents when outdoors, and do your best to minimize standing areas of water. If you have questions about mosquitoes and their control, visit the UF/IFAS Florida Medical Entomology Lab website (https://fmel.ifas.ufl.edu/) and browse the many resources available.
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.
