More About Emerging Roselle Diseases and Pests

Roselle—TYLCV Positive and Anthracnose

In late September, we posted a warning about a new pest found on the Roselle in the VegHeadz garden. Extension agent Mark Tancig subsequently delivered specimens to the UF Plant Disease Diagnostic Clinic for analysis. The analysis report can be seen below. It is not good news. The Roselle is infected by a virus, by a fungus, and two insect pests. The most worrisome part of this report is that these pests and diseases can affect other plants such as cotton, okra, tomatoes, beans, and others.  

Any plants suspected of being infected, either Roselle or any of the other species listed in the report, should be pulled and disposed of in the manner recommended by the lab.

The infestations are not happening just in our garden – the distorted and damaged Roselle leaves have been sighted in other areas of the city as well as in adjoining counties and other areas of Florida.  Additional information can be obtained from the Extension here in Leon County or in your area. This is potentially devastating to home gardeners, market gardeners, and farmers who produce any of the affected species. 

Plant Disease Diagnostic Clinic 155 Research Road Quincy, FL 32351 Phone: 850-875-7140Fax: 352-846-6617  Email: fbiriarte@ufl.edu

PLANT SPECIMEN DIAGNOSTIC REPORT       Specimen # 2025-190

SUBMITTED BY Mark Tancig Leon County Extension Office 615 Paul Russell Rd Tallahassee, FL  32303 tancig00@ufl.edu		PLANT Hibiscus (Hibiscus sp.)		METHOD SUBMITTED Walk-In
		VARIETY Roselle		CLASS Woody Ornamental
		INTERNAL LAB NO.	LAB FEE $40.00	REPLY FROM LAB September 29, 2025
PHONE 850-606-5217	COUNTY LEON, FL	PLANT MATERIAL Leaves		RECEIVED BY LAB September 24, 2025
CONDITION UPON ARRIVAL Good sample, fair information		DIAGNOSTICIAN(s) Fanny Iriarte, Ph.D.
GENERAL OBSERVATIONS Gnarled, deformed leaves. Mottle or mosaic.		DIAGNOSTIC TECHNIQUE(S)     __ Agdia Immunostrip  X  Microscopic __ Reverse transcription-PCR     __ Fatty Acid Analysis  X  Molecular Analysis __ Serological     __ Incubation __ Other __ Techniques     __ Isothermal amplification  X  PCR __ Visual Observation     __ Lab Tests and Services __ Recombinase polymerase amplification      X  Media __ Reverse transcription real time PCR RT-qPCR
GROWER INFORMATION Mark Tancig Leon County Extension Office 615 Paul Russell Rd Tallahassee, FL  32303 850-606-5217 tancig00@ufl.edu		REFERRAL INFORMATION

Diagnosis/Recommendations 

Diagnosis:	Tomato Yellow Leaf Curl Virus (TYLCV) (Begomovirus)
Category:	Virus
Comments:	Your Hibiscus plant tested POSITIVE for Tomato yellow leaf curl virus (TYLCV). TYLCV is one of the most important viral diseases of tomato. TYLCV has been reported to have a diverse host range including 49 plant species belonging to 16 families around the world. In the U.S. it is known to infect plants in the solanaceous family, common bean (Phaseolus vulgaris), and Ornamentals (including Petunia, Lisianthus, hibiscus, poinsettia and others). For more information see: Tomato Yellow Leaf Curl Virus | NC State Extension Publications MANAGEMENT As you know there is no control for viral diseases and the best thing you can do is remove and discard infected plant material away from the site to avoid the spread. It is also important to control the whiteflies to stop the spread of the virus to other host plants nearby. Most of the recommendations for management of whiteflies are related to tomato crop but some information may be useful and applicable to a poinsettia garden in the link below. ENY-478/IN871: Recommendations for Management of Whiteflies, Whitefly-Transmitted Viruses, and Insecticide Resistance for Production of Cucurbit Crops in Florida You may also want to contact Dr. Martini (cc here) for simple methods to control whiteflies in garden setting.
Diagnosis:	Anthracnose (Colletotrichum gloeosporioides)
Category:	Fungus
Comments:	Colletotrichum gleosporioides abundant spores were also recovered from leaf and stem reddish spots. The disease is called Anthracnose. For more information about Anthracnose please see: Anthracnose Disease of Ornamental Plants: A Pictorial MANAGEMENT Remove and discard infected plant material away from the site. Avoid or reduce overhead irrigation, water early in the morning and avoid stress to the plant. Avoid overwatering. Avoid any stress to the plant. Early spring protectant fungicide may help prevent further infections. For possible chemical control recommendations see "Anthracnose" at: 2017 Southeastern US Pest Control Guide for Nursery Crops and Landscape Plantings.
Diagnosis:	Two-spot cotton leafhopper (Amrasca biguttula) (syn. Cotton Jassid)
Category:	Insect
Comments:	Severe damage caused by two-spotted cotton leafhopper (Amrasca biguttula) also known as "Jassid" was also confirmed by our entomologist Dr. Isaac Esquivel. This insect pest, first found late 2024, can cause severe damage on cotton in Florida. It can also attack okra, eggplant, tomato, hibiscus and others. For more information on this pest please see:  Two-Spot Cotton Leafhopper: A New Pest Threat in Florida Vegetables - UF/IFAS Extension Alachua CountyAlso see: PEST ALERT: Two-spot cotton leafhopper For any questions or concern about management of this insect pest, please contact Dr. Esquivel. Please be advised that records produced as a result of this analysis are public records subject to disclosure under Florida law. Plant Disease Diagnostician: Fanny Iriarte, Ph.D. Our lab website: http://nfrec.ifas.ufl.edu/ AND https://plantpath.ifas.ufl.edu/u-scout/index.html

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Summer Often Means Trouble in the Garden

A simple deer fence
around this bean patch.

High temperatures, humidity, too much rain or too little, bugs, diseases. Summer almost always means trouble in the garden. It seems like our latest posts have all been about problems—too much sun on our gardeners, the never ending fight against nutsedge, and marauding deer and two-legged thieves.  One possible solution for deer from a midwestern gardener who has a beautiful garden in deer country—he runs a string or wire around the garden, ties on rags or old socks at intervals, sprays or dips them in vinegar, and the deer don’t bother his garden.

We’ve also noticed our sunflowers deteriorating Advice from Extension Agent Mark Tancig:

Heat and humidity are hard on sunflowers. Also they can suffer from some diseases due to being planted in the same spot, specifically Sclerotinia wilt, head rot, and Phomopsis stem canker. 

Here are links for those:

• Sclerotinia - https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/SclerotiniaSunflower.aspx

• Rhizopus head rot - https://www.sunflowernsa.com/growers/Diseases/Rhizopus-Head-Rot/

• Phomopsis stem canker - https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/PhomopsisStemCanker.aspx    

This is the time for planning and prepping for your fall garden. The VegHeadz had their fall planning meeting recently and are looking forward to a cooler, productive season. 

Final note—Leon County Library Seed Giveaway launches at the main library on Saturday, August 19 at 10 a.m. More information here: https://www.facebook.com/100064630781772/posts/pfbid02nyMAjVX325NxMYj2MJYEra3qzhB4TZNYus9oSSXJuLb6nnvmmsTZBnSSbuGcfVLJl/?mibextid=K8Wfd2

UF/IFAS One-Stop Site for solving Garden Problems

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) has launched a new one-stop site for accessing information to diagnose garden and plant problems.  Information can be found there on plant insects and diseases, integrated pest management (IPM), soil and water, weeds, and more.  If you can't diagnose your problem, resources are available to help you locate someone who can.  Put this site on your desktop or home screen.  You'll be using it a lot.  https://diagnostics.ifas.ufl.edu

Soil Solarization

Solarizing pathways in the
VegHeadz garden

Are you tired of pulling weeds, are insects demolishing your crops, do you suspect you are infested with nematodes?  One solution which lasts through a growing season is solarization. 

The VegHeadz garden has several patches of recurring nut sedge.  We've pulled, dug, covered with cardboard and mulch, all to no avail.  The nut sedge always prevails.  This is a good time of the year for solarization, so we're trying it on several patches in our walkways where the nut sedge is thickest and most persistent.  We'll keep you updated. 

Solarization consists of wetting the soil, covering the area in question with transparent plastic (ours is opaque even though the container said "clear"), sealing the edges, and leaving it to bake in the sun for six weeks.  If there are consistent days of sun for this period, much of the living matter under the plastic will be killed, including weeds, bugs, and nematodes.  For more information, access an excellent article at UF/IFAS on Soil Solarization.

Master Gardener Evelyn Gonzalez 
covers the edges of the plastic with
mulch to seal in the heat

Bacterial Wilt in Tomatoes



Photo courtesy of University of Florida IFAS

Although Bacterial Wilt is said to be a prevalent problem in the Southeast and Florida, we had not experienced it in the VegHeadz Demo garden until this past growing season.  Tomatoes in one raised bed would suddenly wilt -- the whole plant -- and soon die.  The problem was immediately diagnosed by our supervising Extension Agent, Trevor Hylton.  Glenn Berman is the coordinator for that bed, a square foot garden, and he felt challenged to find a solution.  After researching the problem he determined there is not much to be done about the problem, as it is resistant to treatment, and infects the soil in the bed for many years.  See more including identification pictures at:    Bacterial Wilt of Tomato - IFAS

The only solution is to grow varieties of  tomatoes (as well as peppers, eggplant, potatoes, etc., - members of the Salonaceae family) which are bred to be resistant to bacterial wilt.  Glenn located three varieties that were advertised by their sellers to be resistant.  He planted them in the same spot as the tomatoes which had succumbed to the disease.  Only one variety has survived so far - Kewalo.  Glenn planted two of this variety which he had grown from seed, and both are surviving and beginning to bloom. 

This brings to the fore a caution about interpreting and relying on descriptions of plants when you buy seeds or seedlings.  Words like "tolerant of" and "resistant to" don't necessarily mean the plant will be free of disease when grown in an infected location. 

Below is a list of the varieties Glenn grew and the exact description of each provided in the seed catalogs of the companies where he bought them.

Tropic Boy - Evergreen Seeds

"Tropic Boy is a hybrid tomato developed by Takii Seed Company in Japan. Plants are indeterminate and produce large size fruits, 220 grams in weight, with green shouldered and turn to red when matured. This variety is vigorous grower, 6-7 loculi and 5-6 fruits per cluster. Fruits have tough skin and firm meat and crack free, suitable for long distance shipping.  The plant is high tolerant to Bacterial wilt, Fusarium, Nematode and Stemphylium attacks. Very good for tropical area productions."

Neptune - Southern Exposure Seed

"An early- to mid-season fresh market tomato specially bred for heat tolerance and resistance to bacteria wilt which is prevalent in the Southeast and Florida.  Recommended for gardeners and market growers in hot, humid, rainy growing regions where it is difficult to grow tomatoes.  4-oz. red fruits in clusters of 2-4 on short vines.  (67 days determinate)"

Kewalo – Tomato Growers Supply

"This round, red tomato from the University of Hawaii is tolerant to both nematodes and bacterial wilt, serious problems in tropical and sub-tropical climates. It is the only open-pollinated variety we know of that can boast of these traits. While it is well suited for the tropics, it is well adapted to more temperate areas also. Determinate. 78 days."

 

Planting and Harvesting Potatoes

It's time to get our potatoes in the ground.   They should survive just fine, even if we have another cold snap.  If green shoots peek above the ground and a freeze is predicted, just cover them with some straw or hay.

The soil should be light, fertile, and somewhat acidic.  Potatoes like soil between 5.0 and 5.5.  Do not use lime (high pH) soil for potatoes.  High pH soils encourage potato scab disease, which makes the potatoes unsightly, but usually not unusable.  See below for more on soil pH.

Cut the seed potatoes into planting pieces containing one or more eyes.  Allow them to dry and callus over for several days before planting to discourage rotting.  Dig a trench about 6 inches deep. Place potato pieces at the bottom of the trench with eyes up about 18" apart.  Cover with about 3 inches of soil.  When the plants are 5 to 6 inches above the soil, add soil to fill in the trench and as the plants grow, continue to mound up around them.  This will encourage the plants to grow potatoes in layers up the stem, and increase your yield.  Add a 10 to 12 inch layer of pine straw to insulate the soil, keep the potatoes cool and moist, and to keep any sunlight from turning exposed potatoes green and inedible.

For best yields and better storage, potatoes should not be dug until two weeks after the vines are dead.  For earlier harvest, cut the vines and allow the potatoes to remain in the ground for several weeks.  This allows the skins to toughen and reduces skin peeling and bruising, and increases storage time.   If harvesting when temperatures are above 80 degrees, potatoes should be picked up immediately and stored in a cool dark place.  Of course, digging carefully around under the growing plants and stealing a few small "new" potatoes to enjoy in the Spring is one of the pleasures of gardening.  You should be able to find small potatoes just right to eat when the plants start blooming.

Identifying Plant Diseases

Maybe your cabbages don't look like this.  Your tomato plants are turning brown, your peppers have brown spots, or your cabbages are rotting.  What's happening to your garden?  U-Scout, a new website at the University of Florida provides photos and information about vegetable plant diseases.  This new site will help us identify what's going on with our plants.  So far there is information about tomatoes, peppers, cucurbits (melons, cucumbers, etc.), and brassicas (cabbages, kale, collards, etc.).  There are no links to remedies on the site.  That would be a great addition.  For solutions, try Vegetable MD Online sponsored by Cornell University.