Citrus Canker on the Spread in NW Florida

Citrus Canker on the Spread in NW Florida

Citrus canker has made its way to Escambia County and may be more widespread that we realize.  This bacterial disease was first seen in Northwest Florida almost 10 years ago in Gulf Breeze. Given time and the ease of transmission of this disease, we are now seeing affected citrus trees in both the east and west portions of Escambia County.

This disease is specific to citrus with grapefruit, lemon, and lime being the most susceptible to infection.  The disease can infect all above ground tissues and often enters through natural openings and wounds of leaves, stems, and fruit.  If you find an infection early in an isolated area of the tree, you can prune out and double bag the affected tissue for disposal.  Often times, the disease is noticed only after a considerable amount of tissue and fruit are affected making it difficult to keep the disease in check.

Since the bacteria is so easily transmitted through rain and wind, it is difficult to prevent movement during our frequent storm events. People can also spread the disease by movement of unregulated citrus trees, on equipment, and even on clothing.

Citrus canker lesions appear on both the upper and lower surfaces of the leaves. Photo by Beth Bolles, UF IFAS Extension Escambia County

Lower surface with citrus canker. Photo by Beth Bolles, UF IFAS Extension Escambia County







If you suspect a citrus in your landscape has canker, do not bring a sample to your Extension office for identification.  Take a photo of plant symptoms of upper and lower leaves, fruits, and stems so that your local Extension educators can assist with identification.  The University of Florida publication has quality photos and descriptions of the different stages of citrus canker, along with photos of other citrus issues.

Stem lesions on grapefruit. Photo by Beth Bolles, UF IFAS Extension Escambia County.

The bad new for homeowners is that there is not a treatment to cure citrus canker.  If the infection is small (a few leaves or a branch), it may be possible to remove and dispose of the material, following proper sanitation guidelines. Homeowners may also suppress a small infection on fruit by using copper-based fungicides, applied at appropriate intervals. These fungicides only protect plant tissue for a short time by acting as a barrier to infection. See this UF publication for timing of copper sprays for fruit.

Once susceptible citrus are heavily infected, trees will have fruit and leaf drop, along with general decline and dieback.  At this stage of the disease, homeowners should strongly consider removing the tree.  If it can be burned on site in accordance with local burn laws, that keeps the material contained and may reduce disease transmission. Otherwise, all material should be double bagged and sent to a landfill. Do not compost any material onsite or at local composting facilities.  Be sure to follow disinfecting techniques outlined in the University of Florida publication for tools, hands, and clothing.

Since management of citrus canker is so difficult, prevention is the best method to protect your tree.  If you are considering a citrus, choose a more resistant selection outlined in the UF publication, Table 2.  Always purchase a citrus from a certified nursery and follow state guidelines which prohibits all propagation of citrus, unless registered to do so.

Gardening in the Panhandle LIVE Program Summary: Subtropical Fruit

Gardening in the Panhandle LIVE Program Summary: Subtropical Fruit

The Q&A on Subtropical Fruits offered valuable information on many types of subtropical and temperate fruits of interest to homeowners.  Below are the reference materials related to specific questions that were asked along with notes from the panel discussions.

How to protect tropical and subtropical fruit trees from freezes?
Freeze protection of TF crops outside of Miami-Dade County:

Cold protection in South Florida is mainly through irrigation practices. It takes irrigation to run before freeze and continue until freeze is over.

What are the easiest subtropical fruits to grow?
Home Citrus Culture Publications – UF:

What are the best citrus trees to grow on NE Florida?
Tangerine, Mandarin (Owari and Brown select mandarins), & Tangelo Varieties:

Can we grow papayas here?
Growing Papaya in the Home Landscape:

Papayas are grown from a seed, not from air layering or grafts. There are some disease issues from Papaya ringspot virus. May have to start new plants. Less than a year from seed to fruit. Seed can be all male, all female, or have both male and female flowers. Need to get rid of the males. Male flowers hang off the tree where females stick to the stem more.

What are the best varieties of limes to grow in the Panhandle?
Growing “Tahiti” Limes in the Home Landscape:
Tahita and Persian limes are in retail nurseries. These are cold sensitive so plant in protected areas. Key limes would need to be in a container for most people.
Rangpur lime is a lemon and mandarin cross.

Bananas continually produce nice foliage but do not form fruit in 5 years.  What to do?
Maybe not spend any more time trying to get fruit. If the bananas are in a large clump, you don’t want to have a large clump. Cut them back so that you have 3 bananas, one large, one medium, and one small so that you get lots of light. That is the key to fruit. Remove brown leaves.

Can we grow a Barbados cherry successfully?
Malpighia glabra, Barbados Cherry:
Small tree to about 6 feet x 6 feet. Mild flavor. Not really suitable for North Florida. Needs sunlight for fruit.

Can we get the transgenic papaya that is immune to the Ringspot virus?
TREC Fruit Specialist has the papaya but it is not legal to introduce them into Florida at this time.

Advice on growing kiwi vine.
Growing Kiwis in FL:
Temperate fruit that requires chill hours. Golden varieties developed by Auburn University. AU Golden Dragon and AU Golden Sunshine. Need a substantial trellis. Male and female vines so male vine for every 2-3 females.

Crestview gets fairly cold in late winter. What fruit trees do well here?
Dooryard Fruit Varieties:

Will Papaya fruits reach maturity in NW Florida?
Growing Papaya in the Home Landscape:

Papayas do not like the cold. Probably not likely to produce a fruit but can give it a try.

What about pineapples?
Good option in a container. Bromeliad that is terrestrial that is watered through the roots.

I planted an arbequina olive tree and it’s struggling. Keeping in pot and protected from freezing but not thriving.
Olives for Your FL Landscape:

Olives like a more consistent temperature than the Panhandle offers. Needs excellent drainage.

Mexican avocado has survived freeze and flooding but still not thriving. Why?
Avocado IPM:
Hass avocado, smaller ones from CA and Mexico. South Florida is too warm to grow Hass but it may work in North Florida. Green skinned avocado is grown in South Florida. More tasty. Florida avocados need a little cool weather to initiate flower and then fruit.

Avocados will not like wet soils.

Will lychee and avocado grow in Pensacola?
Red fruit, white inside, similar to a grape but sweeter. Needs chill hours. 2018 lychee mite came into Florida and now in 13 counties. Difficult to manage.

Shade-tolerant subtropical fruits?
Fruit needs sun. Monstera deliciosa, Swiss cheese plant, produces an edible fruit grows in shade. Definitely needs protection. DO NOT eat fruit early or you will have mouth pain. Fruit should be falling apart.

Pawpaw is not tropical but grows in shade.

How to trim fruit trees?
Hand pruning and training of tropical and sub tropical fruit trees:

Often prune for size control in South Florida to encourage lateral growth and get sunlight into the center.

Which banana trees thrive here?
Banana Growing in the Florida Home Landscape

What subtropical fruits are garnering the most interest in the panhandle right now?
Loquat Growing in the Florida Home Landscape:

Mangos are of most interest in South Florida

What about akee?
Caribbean fruit related to lychee. Do not eat before ripe or you will die.

The good pH for blueberries and raspberries
Blueberry Gardener’s Guide:

What plum varieties are recommended?
Fruit Tree Recommendations for AL:

Finger limes are the new hot crop at the TREC.

Video: Perennial Peanut Considerations as a Lawn

Video: Perennial Peanut Considerations as a Lawn

Turfgrass remains a popular groundcover for most home landscapes. Perennial peanut offers potential as a turfgrass companion in North Florida. Learn the pros and cons of using perennial peanut with existing turfgrass with UF IFAS Extension Escambia County.

Video: Collecting a Quality Plant Sample

Video: Collecting a Quality Plant Sample

Having a quality turf or plant sample is important to help us at UF IFAS Extension diagnosis a problem or identify a plant. Learn how to collect a sample of both turf and plant material if you will be bringing a sample to your local UF IFAS Extension County office.

A Favorite Native Shrub

A Favorite Native Shrub

Strawberry bush with new spring growth. Photo by Beth Bolles, UF IFAS Extension Escambia County.

When I was first planting a landscape in 2001, I wanted to include some interesting native plants to provide a natural look for the back edges of the property.  I was able to find a few less commonly sold natives from a small local nursery including a Bigleaf magnolia, Vaccinium, Sourwood, Cinnamon fern, and Strawberry bush.

Twenty years later, I am still enjoying these natives in my landscape and they are doing well despite my sandy, well drained, nutrient poor conditions.  One of my favorites of this group is the Strawberry bush, Euonymous americana.

Strawberry bush is a deciduous shrub that grows about five feet tall. It has multiple stems with new stems forming each season.  Since my yard is so dry, my clump is by no means out of bounds after 20 years of growth.  Small pale green flowers grow from the nodes in spring.  For most of the year, you forget about this plant until one day in the fall, you notice brilliant red fruits that split open to show orange seeds.  Another common name is Hearts-a-bustin’.

Fall color with Strawberry bush. Photo by Beth Bolles, UF IFAS Extension Escambia County.

Despite one of its common names, Strawberry bush is not grown as an edible for people but serves as a wildlife food source.  Deer may enjoy leaves and twigs and many birds and small mammals will eat the seeds.

If you find a local nursery that is growing a few, consider adding Strawberry bush to a shaded spot in your landscape.