by Mark Tancig | Sep 18, 2017
Hopefully, by this time of year, most north Florida gardeners have harvested their figs and are enjoying fig preserves or fig bars. But if you’ve noticed your fig leaves dropping a little early, it may be a sign of the fungal disease Fig Rust (Cerotelium fici).
Figs are a great fruit tree for the north Florida home garden. Not only do they provide a tasty reward (if you can keep the birds and squirrels away), but they are fairly easy to maintain and are bothered by relatively few pests and diseases. One of the few diseases that can be common, however, is fig rust, especially when conditions are favorable. In the case of fig rust, a fungus, warm humid weather is what it likes and well, we have plenty of that.
Figs are a great fruit tree for North Florida. Credit: Mary Derrick, UF/IFAS.
The first signs of the fig rust disease are small yellow to yellow-green spots/lesions on the upper surface of the leaf that turn a reddish-brown color as they get larger. A heavy infestation causes the leaves to turn yellow and drop early. While fig rust does not injure the fruit, repeat occurrences of premature leaf drop can adversely affect the overall health of the tree, resulting in yield loss. Another concern is that if the leaves drop too early, the tree will flush out with new growth heading into winter. This new growth can be injured by early freezes and cause a loss of fruit the following season.
Fig rust on leaves. Credit: UF/IFAS.
What can you do to prevent and/or cure fig rust? Unfortunately, once you see the yellowish-green/reddish-brown spots on the leaves, it’s too late to provide any control. As always, proper cultural practices can help. Pruning the tree to provide adequate airflow keeps the leaves as dry as possible during our humid summers. Remember to prune fig trees in Florida after fruit harvest, not in the dormant season, since fruit is borne on previous year’s growth. Another cultural control to prevent fig rust is to rake diseased leaves out from under the tree. The fungal spores in the fallen leaf litter pass the disease on to next year’s leaves. Other cultural controls include providing adequate moisture and placing a healthy dose of mulch around the tree. Figs require minimal fertilizer. Using a general complete fertilizer with micronutrients (such as a 10-10-10), young trees should receive 1 cup (1/2 pound) and mature trees 4-8 cups (2-4 pounds) per year.
There are currently no chemical controls approved for fig rust in Florida. The classic Bordeaux mix is recommended by various authors to be used as a preventative fungicide during the dormant season, before the lesions appear on the leaves. The Bordeaux mixture is a mix of copper sulfate, lime, and water in a 1:1:10 ratio and is considered an organic pesticide. This mix has been used since the late 19th century and was discovered by accident after botanists and farmers realized that grapevines sprayed with the mix to deter theft had less fungal problems. As with any pesticide, be cautious when using. Overuse of copper-based fungicides can cause copper to build up in soils, leading to potential issues to plant and human health.
While figs are generally worry free for our area, fig rust is one disease to be on the lookout for. Good gardening practices can reduce the occurrence of this disease and ensure a bountiful harvest. For questions on growing figs or about the fig rust disease, visit the UF/IFAS EDIS website – edis.ifas.ufl.edu – or contact your local Extension office.
by Mark Tancig | Aug 1, 2017
Florida’s panhandle has received quite a bit of rain this summer. In the last three months, depending on the location, approximately 15 to 35 inches of rain have come down, with the western panhandle on the higher end of that range. In addition to the rain, we all know how hot it has been with heat index values in the triple digits. And who can forget the humidity?! Well, these weather conditions are just the right environmental factors for many types of fungi, some harmful to landscape plants, most not.
In the classification of living things, fungi are divided into their own Kingdom, separate from plants, animals, and bacteria. They are actually more closely related to animals than plants. They play an important role on the Earth by recycling nutrients through the breakdown of dead or dying organisms. Many are consumed as food by humans, others provide medicines, such as penicillin, while some (yeasts) provide what’s needed for bread and beer. However, there are fungi that also give gardeners and homeowners headaches. Plant diseases caused by various fungi go by the names rusts, smuts, or a variety of leaf, root, and stem rots. Fungal pathogens gardeners may be experiencing during this weather include:
- Gray leaf spot – This fungus can often show up in St. Augustine grass lawns. Signs of this fungus include gray spots on the leaf (very descriptive name!). This disease can cause thin areas of lawn and slow growth of the grass.
Gray leaf spot on St. Augustine grass. Credit: Phil Harmon/UF/IFAS.
- Take-all root rot – This fungus can attack all our warm-season turfgrasses, and may start as yellow leaf blades and develop into small to large areas of thin grass or bare patches. The roots and stolons of affected grasses will be short and black.
Signs of take all root rot. Credit: UF/IFAS.
Powdery mildew – This fungus can be found on many plants, from roses to cucumbers. It looks like white powder on the leaves and can lead to plant decline.
- Armillaria root rot – This fungus can infect a variety of landscape plants, including oaks, hickories, viburnums, and azaleas. Symptoms can include yellowing of leaves and branch dieback, usually in adjacent plants. Old hardwood stumps can harbor this fungus and lead to the infection of nearby ornamentals.
Because fungi are naturally abundant in the environment, the use of fungicides can temporarily suppress, but not eliminate, most fungal diseases. Therefore, fungicides are best used during favorable conditions for the particular pathogen, as a preventative tool.
Proper management practices – mowing height, fertilization, irrigation, etc. – that reduce plant stress go a long way in preventing fungal diseases. Remember that even the use of broadleaf specific herbicides can stress a lawn and exacerbate disease problems if done incorrectly. Since rain has been abundant, irrigation schedules should be adjusted to reduce leaf and soil moisture. Minimizing injury to the leaves, stems, and roots prevents stress and potential entry points for fungi on the move.
If you think your landscape plants are suffering from a fungal disease, contact your local Extension Office and/or visit the University of Florida’s EDIS website at http://edis.ifas.ufl.edu for more information.
by Mark Tancig | Jun 22, 2017
Recent rains in the panhandle have kept many gardeners indoors. While we’re mostly watching the rain from inside, there are some lawn and landscape tasks to consider.
The most obvious is to turn off any automatic irrigation systems. Although rain shut-off devices are required for all automatic irrigation systems in Florida, many homeowners’ systems are not properly installed, are turned off, or are absent all together. Irrigating during times of adequate rainfall not only wastes a precious natural resource, but it can also be damaging to your turf and landscape plants by creating the perfect conditions for disease, especially fungi.
A rain shut-off device ensures that your irrigation system doesn’t come on during rainy weather. Photo by: Mark Tancig, UF/IFAS.
Something else to consider during all of this rain are potential mosquito breeding sites. Our most irritating mosquito species, those day-biting Asian tiger mosquitoes, love to breed in any small or large, water-holding containers around the house, including birdbaths, plant pot saucers, watering cans, five-gallon buckets, tarps, rain barrels, and the list goes on. The best method of control is to drain these containers every three to five days to prevent mosquito larvae from hatching. Another way to reduce larvae from hatching is to use a Bti product, which come in donut shaped dunks or as crumbles that can be sprinkled in the container. Bti controls mosquito, blackfly, and fungus gnat larvae, but does not harm beneficial insects and animals like birds, bees, butterflies, lizards, and frogs. If mosquitoes from the swamp or wetland behind your lot worry you, remember that those ecosystems have a diversity of insects that prey on mosquito larvae. Those containers in the yard do not have predators and can be a large source of the most aggravating mosquito species. For control of larger areas, including those natural ecosystems, contact your local mosquito control agency for assistance.
Bti bits are a way to prevent mosquito larvae from becoming biting adults. Photo by: Mark Tancig, UF/IFAS.
If you like to play in the rain a little, this is a good time to walk around and observe any runoff issues in the yard (make sure to do this only when it’s safe!). The ideal situation is to have runoff drain away from the house and percolate into landscaped areas. When surveying the yard in the rain, things to look for include areas of standing water (that could be a good location for a rain garden) and areas where erosion may be occurring (consider using berms or plantings to better direct and slow the water). Before doing any major drainage work, always check with your local building department. Some municipalities may require permits to ensure your improvements do not affect your neighbors or others downstream.
Rain gardens can turn a low, soggy spot into an aesthetic addition to your yard. Photo by: Courtney Schoen, TAPP.
If you have any questions about rain shut-off devices, mosquito control, or stormwater runoff, contact your local UF/IFAS Extension office for more information. Enjoy the rain; it will be sunny and hot before you know it!
by Mark Tancig | May 25, 2017
One of the main Florida-Friendly Landscaping principles is to plant the right plant in the right place. In Florida, not only does this apply to the zone you’re in, soils you have, and light conditions in your garden, but also ensuring that invasive, exotic plant species are not used. While most of us have heard about invasive, exotic plants – those that invade and disrupt our unique natural habitats – some may not know where or how to find out which plants are, in fact, invasive and exotic. Some of the more famous invasive, exotic plant species, such as kudzu and hydrilla, are familiar to us and we may have an idea of a plant in our garden that is “aggressive”, but how do we know for sure? Since only a handful of the worst invasive, exotic plants are legally prohibited from being sold, how do we know if a plant we are considering purchasing at our local nursery or another plant already in our gardens is an invasive, exotic? A quick internet search for Florida invasive plants gets you various sources of information. How do you choose which to use?
The unique habitats of Florida need our help. Prevent the spread of invasive, exotic species by planting Florida-Friendly plants. Source: Mark Tancig/UF/IFAS.
Fortunately, the researchers at UF/IFAS want you to be able to find the best information in one spot – the UF/IFAS Assessment of Non-Native Plants in Florida’s Natural Areas. This site systematically reviews individual plant species and provides a recommendation as to whether it should be used in North, Central, or South Florida landscapes. Many landscape plants have been reviewed – over 800 – and more are added to the site as reviews are completed. The UF/IFAS Assessment also reviews cultivars of known invasive, exotic plants to ensure that they are sterile and will not revert back to their wild type or hybridize with known invasives, or even closely related native species.
The UF/IFAS Assessment is a simple, convenient source for deciding if a plant should be used in your Florida landscape.
To use the site, simply visit the main web address – assessment.ifas.ufl.edu – and begin typing in your plant name in the search bar. You can begin spelling the scientific or common name and it will start showing possible results as you type. Once you select the plant you’re interested in, it will take you to a new page with photos of the plant, some general information, additional links, and, most importantly, the assessment conclusion for each zone. The conclusion will be one of the following:
- Not considered a problem species at this time,
- Caution, or
- Invasive
Of course, if it’s not a problem, then feel free to use and share that particular plant. If it is a caution plant, then it may be used, but you will want to be extra careful in where you plant it. Those may be better suited as potted plants or planted in areas that are confined, to limit its potential spread. If it’s invasive, don’t plant it.
Caution plants are reassessed every two years while those that are not considered a problem species or are considered invasive are reassessed every ten years.
Another way to use the UF/IFAS Assessment is to filter all reviewed plants by various criteria you’re interested in. If you select assessments on the main page, it will lead you to a list of all reviewed plants. A filter button allows you to choose geographic zone, conclusion type, and growth habit, among some other criteria. This will create a list that can then be exported to a Microsoft Excel table.
As you can see, UF/IFAS is trying to make it easy for you to determine which plants can be used in the landscape without potentially spreading and causing disruption to our unique natural areas.
If you have any questions about individual species that have or have not been assessed, contact your local County Extension Office.
by Mark Tancig | Apr 24, 2017
Source: UF/IFAS.
Impatiens are a very popular annual, bedding plant that provide a nice burst of color in the landscape. The traditional Impatiens (Impatiens walleriana), or touch-me-not, is the one that most gardeners know as needing part shade, but there are also the New Guinea Impatiens (Impatiens hawkeri) that are able to tolerate more sun. In addition to being able to withstand more sunlight, the New Guinea Impatiens also have larger flowers and leaves. Another highlight of the New Guinea impatiens is their increased resistance to downy mildew, a major concern for growers of touch-me-nots, especially in south Florida.
While native to the Old World, Impatiens are not known to invade Florida natural areas but may reproduce by seed. Touch-me-nots are known to spread easily be seed. An interesting fact about Impatiens is their bursting seed pods that can send seeds several feet from the parent plant. This characteristic is what led to the scientific name Impatiens – for impatient – and one of the common names – touch-me-not.
May is a good time to plant Impatiens in north Florida. They prefer slightly acidic soil and should be planted at a 12-18 inch spacing. Impatiens work well as a border planting or in mass plantings. While New Guinea Impatiens tolerate more sun, they still would prefer some afternoon shade. Those growing in full sun will need extra care to ensure they remain well watered. An all-purpose plant food can be applied at monthly intervals for best performance.
Some common varieties of touch-me-nots include ‘Accent’, ‘Blitz’, ‘Carousel’, ‘Dazzler’, ‘Impact’, ‘Impulse’, and ‘Super Elfins’. Common New Guinea Impatiens varieties include ‘Celebration Candy Pink’, ‘Celebration Light Lavender’, ‘Nebulus’, ‘Equinox’, ‘Sunglow’, and ‘Tango’. The newer ‘Sunpatiens’ variety is quite popular and comes in different forms – compact, spreading, and vigorous.
Source: UF/IFAS.
If you have any questions regarding Impatiens, please contact your local UF/IFAS Extension Office or visit our EDIS website at www.edis.ifas.ufl.edu.
