Hickory Gall and Anthracnose, a Deadly Combination?

Hickory Gall and Anthracnose, a Deadly Combination?

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.

Whole Hickory Gall

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.

Gall Half

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

Gall Larva

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.

 

Centipedegrass Weed Control:  You Only Need 3 Herbicides!

Centipedegrass Weed Control: You Only Need 3 Herbicides!

Nearly everyone likes turfgrass lawns.  They’re pretty and green.  They filter water, chemicals, and nutrients before they enter our groundwater systems.  They provide a recreation spot for people and pets.  But lawns also come with maintenance tasks, one of which is weed control.  Fortunately, keeping our common Centipedegrass lawns relatively weed free is as simple as smart management and utilizing herbicides effectively.  Though the number of herbicides available for purchase can be overwhelming, you only need three to keep weeds at bay – a selective grass herbicide, a strong broadleaf herbicide, and a sedge herbicide!

Dollarweed in flower

Dollarweed, one of the toughest broadleaf weeds for homeowners to control. Picture courtesy of  Julie McConnell, UF/IFAS.

First up on the essential herbicide list is the selective grass herbicide Sethoxydim.  While most folks’ weed focus is centered on broadleaf weeds, grassy weeds like Crabgrass, Bahiagrass, Goosegrass, and others can be just as problematic and make for a very unsightly lawn.  Enter Sethoxydim.  Cheap and easy to find, Sethoxydim is offered as the active ingredient in many branded products like Fertilome Over the Top Grass Killer, Hi-Yield Grass Killer, and many more.  These products control weedy grass species without seriously harming Centipedegrass or broadleaf ornamental trees and shrubs (Centipedegrass may temporarily be yellowed after sethoxydim application but will recover).  Not only will it kill out the unwanted grass growing in your Centipede, but it will also remove these weeds from your flower beds!

Second, having a strong broadleaf herbicide on hand is necessary.  I say “strong” because many of the homeowner grade products available at garden centers simply don’t have the “juice” to control tough broadleaf weeds like Dollarweed, Doveweed, Virginia Buttonweed, and others.  For this job, I prefer to use a commercial grade 3-way product like Celsius WG by Bayer.  Celsius WG is a 3-way combination herbicide with a healthy dose of Dicamba as its primary ingredient.  Though Dicamba is a notoriously volatile chemical known to cause damage to unintended plants through drift in hot weather, combining it with the two other products in Celsius WG makes it safe to use in lawns, even in the heat of summer.  While strong broadleaf herbicides like Celsius WG are expensive on the front end, don’t let that deter you.  These products wind up being very cost effective in the long run due to minute mixing rates (one bottle goes a very long way in most residential lawns) and effectiveness – you simply will not need to waste time and money spraying lawn weeds over and over to obtain control like is necessary with lesser products – one or two applications will solve the toughest broadleaf weed problems.

Finally, any good lawn weed control program will include a quality sedge control herbicide.  Sedges (often called “nutgrass”) look like grasses but are a completely different category of plants and as such, require specialized herbicide chemistries to achieve control.  Sedge weeds prefer wetter areas of lawns, though they can occur in pretty much any lawn site and are very unsightly.  For this weed category, there are several options available to homeowners.  The one that consistently provides the best control in lawns is Halosulfuron-methyl, the active ingredient in the aptly named product Sedgehammer.  Conveniently coming in individually pre-mixed packets for small lawns or a larger bottle when more acreage is to be treated, Sedgehammer couldn’t be easier to mix and use. While Sedgehammer and similar products are extremely effective in controlling various sedge weeds, they tend to work very slowly, and patience is required.  Weeds immediately stop growing following a Sedgehammer application, but it can take up to three weeks to notice the sedges dying.

While having and using the above three herbicides can control almost any weed homeowners may encounter in their lawns, it is important to remember that herbicides are not substitutes for proper lawn management.  When good cultural practices in lawns are followed, such as mowing at the correct height, only watering when necessary, following UF/IFAS fertilizer recommendations, etc., chemical weed control may not even be necessary in many cases!  Also, once the decision to purchase and use chemical herbicides has been made, it is critical that one always read the label before using any herbicide product.  This ensures safe and effective use of the product; the label is literally the law!

For assistance in choosing the correct herbicide for your lawn and other lawn care concerns, contact your local UF/IFAS Extension Office!  Happy Gardening!

 

Landscape  Q & A

Landscape Q & A

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

 

Controlling Torpedograss

Controlling Torpedograss

One of the most conspicuous outcomes from Hurricane Michael was the complete disruption of local lawns and landscapes.  Giant holes where tree roots once existed, ruts and compacted ground from clean-up equipment, and formerly shaded acres flooded with fresh sunshine were three very common situations property owners suddenly found themselves faced with.  An unforeseen consequence of all this newly bare ground ripe was the intrusion by a variety of very aggressive weeds.  One invasive exotic weed that has made itself right at home in many county landscapes following Michael and that I’ve seen lots of lately is Torpedograss (Panicum repens).

Often brought into landscapes with “fill-dirt” and “topsoil” applications or spread through mowing, Torpedograss is an aggressive perennial grass in the same plant family as Bermudagrass and Cogongrass.  Like many invasive exotic species, Torpedograss was introduced into the United States in the late 1800’s from its native Africa and Asia as a potential forage crop.  Unlike its cousin Cogongrass, the Torpedograss is highly palatable to cattle and so gained a quick following among the ranching community.  Unfortunately, over the next century, Torpedograss had left the pasture and turned into one of the biggest pest plants in Florida, ruining many a lawn, taking over 70% of the state’s public waterways, disrupting native marshlands, and costing Florida over $2 million a year to control!

Torpedograss growing in a Calhoun County gravel driveway. Photo courtesy of Daniel Leonard.

Torpedograss spreads rapidly through underground, sharply pointed, white-colored, “torpedo-like” growing tips and can dominate wet or dry areas in short order.  The species often hides in lawns when mixed in and mowed with other turfgrasses (especially Zoysiagrass, which it closely resembles), growing unnoticed until infestations are severe and control options are few.  This makes scouting for the weed and accurate identification crucial!  Torpedograss can be identified by its bluish-green leaf and stem color, hairy leaf edges, stiff overall appearance, distinctive panicle-type flowers, and can grow quickly to 3’ or so in height, spreading indefinitely.  Though it initially can resemble other turf species, once you know what you’re looking for, Torpedograss stands out visually amongst its competitors.

After identifying Torpedograss, control methods can be chosen depending on the site it has infested.  In lawns, options vary based on turf species.  If infestation occurs in the common Centipedegrass and Bahiagrass lawns of the Panhandle, options are few.  Products with the active ingredient Sethoxydim (Poast, Fertilome Over the Top, Southern Ag Grass Killer, etc.) can suppress Torpedograss growth in these situations but will not destroy it and are not permanent options.  If the area infested is not large, killing the whole spot out with a non-selective herbicide like Glyphosate (Roundup and generics) and then resodding is probably a better option.  In Bermudagrass or Zoysiagrass lawns, products with the active ingredient quinclorac (Drive and generics) are very effective at controlling Torpedograss without having to go the “nuclear” glyphosate route.  Unfortunately, there are no effective controls for Torpedograss in St. Augustinegrass lawns.

In landscaped beds, Torpedograss is somewhat easier to control.  Hand pulling in beds can be effective where new invasions occur but are impractical once the weeds gain a strong foothold.  Once that occurs, chemical control is required.  In bare or mulched areas away from plants, careful spot spraying in bare areas with a 2-3% glyphosate solution is extremely effective.  Where the Torpedograss has grown into and through landscape plants, an “over-the-top” application of fluazifop (Fusilade) will take out the weed without harming most ornamental plant species!  (Be sure to check the Fusilade label to make sure your ornamental plant species are safe to apply to!)

Torpedograss is one of the most serious, yet overlooked, invasive plants that occurs in Florida.  However, through prevention and control techniques like cleaning mowers when mowing infested areas, accurate identification, and prompt, effective herbicide use, you can keep the weed from taking over your lawn and landscape!  For assistance in identifying and controlling Torpedograss and other lawn weeds, contact your local UF/IFAS County Extension office!  Happy gardening!

 

Let’s Talk Beneficial Insects

Let’s Talk Beneficial Insects

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

It’s Green, Gelatinous and in My Lawn

It’s Green, Gelatinous and in My Lawn

The lawn is a source of pride for most and anything out of the ordinary causes alarm.  Now image finding something that looks like lumpy green jelly in your turfgrass and it doesn’t go away.  You try raking it, spraying it, covering it, and it still comes back time and time again.  One of the things we see in late spring/early summer turf is a reemergence of cyanobacteria (Nostoc), sometimes confused with algae because of green coloring and this remains all summer long.

Dehydrated cyanobacteria in a centipedegrass lawn.

Unlike normal bacteria that needs a food source, cyanobacteria contains chlorophyll and produces its own food source through photosynthesis which allows it to grow on bare sandy soils, fabric mats, concrete sidewalks, plastic, and yes even your lawn.  Besides the green pigment, it also produces a blue pigment and is why we call it cyanobacteria which means blue-green bacteria.  In addition to photosynthesis, cyanobacteria can also fix nitrogen, and are believed to produce cyanotoxins and allelopathic compounds which can affect plant growth around them.

Cyanobacteria are considered one of earth’s oldest organism and they have tremendous survival capabilities. They can dry out completely, be flat, flaky, black-green dried particles in your lawn and once rehydrated, spring back to life.  If you happen to notice it spreading throughout your yard, remember that pieces of the organism can stick to your wet shoes or lawnmower tires and be transported unintentionally.

The question then becomes how to control the cyanobacteria and reclaim your turfgrass.  The first solution is to have a healthy lawn.  Cyanobacteria likes poorly-drained compacted soils.  This same condition is unfavorable to turf growth and why you end up with bare spots and establishment.  Reduce soil compaction by using a core aerator, and then adding organic matter.  This will increase drainage, gas exchange, and encourage microorganism populations which I like to call soil pets.  Spike aerators only push the soil particles aside and don’t really loosen as well.  Try to reduce low lying areas in the lawn where water sits after rainfall and irrigation.  You might have to till and reestablish those areas of the yard.

Hydrated cyanobacteria

The same cyanobacteria pictured above 24 hours after being rehydrated in a petri dish of standing water.

Controlling the amount of water Mother Nature gives us and humidity levels during summer is not possible, but you can control your irrigation whether it be automatic (sprinkler system) or hand-watered.  During the rainy season, you should be able to get by with only rainfall and shut off your system.  If needed during extended dry weeks, it is easy enough to turn the system back on.  It is thought that cyanobacteria likes phosphorus which is another reason to use little to no phosphorus in your lawn fertilizers.

As you begin to rid your lawn of cyanobacteria, remember when fully hydrated it forms a slippery surface so be careful walking on it.  Cultural practices will be more effective in controlling the spread versus using chemical methods.  Cultural solutions are safer for your lawn, yard and all of the wildlife that visits.  If you need help with your cyanobacteria, please contact your local Extension office and we are always happy to assist.

A special thanks to Dr. Bryan Unruh, UF/IFAS for his assistance in identifying the cyanobacteria.

For additional information, please read the sources listed below.

 

 

 

 

Biology and Management of Nostoc (Cyanobacteria) in Nurseries and Greenhouses.  H. Dail Laughinghouse IV, David E. Berthold, Chris Marble, and Debalina Saha

Rain, Overwatering Can Cause Slippery Algae to Pop Up in Turfgrass.  C. Waltz

Nostoc.  N.J. Franklin