by Mark Tancig | Jan 13, 2022
Asian citrus psyllid, Diaphorina citri. UF/IFAS/Entomology Photo: Michael Rogers.
In late 2016, as many of us were enjoying the harvests from our backyard citrus, a bacterial plant disease that can affect all citrus, citrus greening, was widespread in central and south Florida but had not made it this far north. That year, the vector, the insect that spreads the disease from tree to tree, had been found in Leon County and a few other surrounding Panhandle counties, but the disease had not. By mid-2017, the disease had been confirmed in Franklin County and we hoped that our cooler temperatures could keep the insect and disease at bay. Well, I regret to inform you that the disease has also now been confirmed in Leon County, growing in a residential yard in Tallahassee. Now that it is confirmed in non-coastal (and cooler) north Florida locations, I thought a review of the signs and symptoms – as well as what to do with your tree if you suspect or confirm greening – would be helpful.
The tricky part about diagnosing citrus greening is that it has symptoms that look very similar to soil nutrient deficiency symptoms, especially when first infected. This is a good time to mention that citrus require certain micro-nutrients for optimal growth and a citrus-specific fertilizer product should be used when applying fertilizer. Both the disease and certain nutrient deficiencies cause yellowing of the leaves. With greening, the yellowing is typically blotchy and/or not in any particular pattern. Nutrient deficiencies typically cause unique patterns of yellowing, such as a V-shape or artistic-like symmetrical patterns on each side of the leaf’s midvein. The soil’s acidity, or pH, can also cause some nutrients to not be taken up by the plant even if they are present. Soil testing, available from your local UF/IFAS Extension office, and scheduled fertilizations with a citrus-specific fertilizer can ensure that nutrients are not to blame for the discoloring of leaves. More advanced stages of the disease cause such symptoms as leaf drop, fruit drop, lop-sided fruit, uneven inner fruit cores, and reduced fruit quality.
Citrus greening symptoms of the fruit. Photo by Brooke Moffis.
A more obvious sign of potential problems for your citrus are the presence of the insect vector, the Asian citrus psyllid. This is a tiny little insect that goes from one leaf to the other sucking up plant saps for food and unknowingly spreading the bacterium responsible for citrus greening. You can monitor for them by looking closely at the new flushes of growth. If the psyllids are present, you will likely notice most their small, peach-colored eggs and/or white, waxy secretions. If found, it doesn’t necessarily mean that your tree has greening, but you will want to minimize the chance that they could carry it to your tree. The psyllids can be treated with pesticides, ranging from the less harsh options (horticulture oils, neem oil, kaolin clay) to the more hardcore stuff (malathion, carbaryl, imidacloprid). Of course, always read the label of any pesticide before use and/or consult a qualified landscape professional for assistance.
Blotchy leaf symptom of citrus greening. Photo by Jamie D. Burrow.
If you suspect your tree is infected, a diagnostic test can be performed by UF/IFAS plant pathologists at the North Florida Research and Education Center (NFREC) in Quincy to confirm. The test does cost $50, which may seem a little steep, but it’s an expensive lab analysis to run and may be worth piece of mind.
If citrus greening is confirmed in your tree, the right thing to do, unfortunately, is to remove and burn the plant material as there is no known cure. While the Florida Department of Agriculture and Consumer Services (FDACS) doesn’t have any removal requirements for infected dooryard citrus, tree removal is best to prevent additional spread of the disease to other trees, especially those grown by commercial producers in our area. This may seem drastic but eventually the health of the tree and quality of the fruit will decline to a point where you will want to remove it anyway. Don’t forget that movement of any citrus plant outside of the state is prohibited for the very reason of preventing spread of citrus diseases.
You may be asking, “Is it okay to replace it with another citrus tree?” The answer is yes you can, but you do risk re-infection and will want to be monitoring the new planting.
You may also be thinking, “What is going to happen to Florida citrus?” That’s a question that many researchers at UF/IFAS are trying to answer. There is some hope that intense irrigation and nutrient management, as well as specific pruning practices, can help infected trees continue to be profitable for commercial growers. Recently, UF/IFAS researchers were awarded several grants to try and figure a way out of this problem. Some of the lines of research focus on exploring the resistance found in different citrus varieties, including an Australian lime that appears to be greening resistant. This could potentially be used as a future rootstock. Another approach is to try and treat the plants with a particular peptide that would prevent the disease from binding in the insect’s gut. Isn’t that amazing?
Until a fix is found, we should be monitoring for this disease in our area and taking steps to reduce its presence through controlling the psyllids and removing infected trees. If you suspect a tree has greening, please contact your local county Extension office to review the symptoms and discuss your options.
Much more information on citrus greening is available at the following Ask IFAS website: https://edis.ifas.ufl.edu/entity/topic/citrus_greening and from this 2017 article – https://nwdistrict.ifas.ufl.edu/phag/2017/03/03/disease-alert-citrus-greening-and-asian-citrus-psyllids-found-in-the-panhandle/.
by Ray Bodrey | Jan 13, 2022
January and February are typically the coldest months in Florida. Low temperatures can damage even the more cold-hardy plants. However, there are measures that can be done to help cold-damaged plants recover.
After a frost or freeze, see if your plants are dry. Even injured plants need water. Plants can be greatly damaged if the temperature drops suddenly, as they have no time to acclimate to the freezing temperatures. These freezing temps cause ice crystals to form in plants cells. These crystals expand, rupturing the cell walls and preventing the plant from maintaining shape. If severe, this can certainly kill tender plants. On more cold hardy plants, damaged foliage will appear wilted and curled down. In a few hours or days, it will darken and turn black. Flowers, buds, and new growth often dieback under freezing temps.
After freezing temperatures occur, it’s important to remove damaged leaves and flowers as soon as they turn brown or black. This will help prevent diseases from occurring. Pruning should be postponed until cold temperatures are no longer expected and new growth begins to appear on the plant. This practice ensures live wood, which appears dead from losing its leaves, is not mistakenly removed from the plant. Cold damaged wood can be detected by examining the cambium layer (under the bark) of the plant. If it has black or brown discoloration, it is damaged and should be pruned back behind these points. Plants should be fertilized in the spring, to encourage new growth.
Cold damage. Photo Credit: University of Florida/IFAS
What about proactive care? You can accomplish this by moving potted plants indoors and covering tender landscape plants with a protective covering. Protective covering can include old bed sheet, pieces of material or fabric, and cardboard boxes. Be careful not to let the protective covering touch the plants. The surface of the covering will become as cold as the air temperatures and may damage any tender leaves it encounters. Also, don’t forget to remove the covering the next day when temperature raises this is important so the plants do not “bake” in the warmer temperatures. Plants placed near the house, lights, or other structures, which shelter them from wind, will be more protected than those fully exposed to the cold air.
Use frost cloth to completely cover cold sensitive plants. Be sure to make complete contact with the ground and use heavy objects to keep the fabric secure. Photo by Jonathan Burns.
For more information on freeze damage plants contact your local county extension office.
Supporting information for this article can be found in the UF/IFAS Extension EDIS publication: “Cold Protection of Landscape Plants”, by Sydney Park Brown: https://edis.ifas.ufl.edu/publication/mg025
by Matt Lollar | Jan 6, 2022
A mixed vegetable garden. Photo Credit: eXtension.org.
It’s never too early to start thinking about your spring vegetable garden. Have you ever wondered how much it costs to grow your own vegetables? Does it cost less to grow your own vegetables or buy them from the grocery store or farmers market? A number of factors are involved with answering these questions and budgeting for your home garden.
Materials
The materials used are specific to your own vegetable garden. If you do everything by hand you may need a hoe, rake, and spade along with a number of other tools you can use from year to year. When budgeting for you garden you would need to think about the life expectancy of these tools. Let’s say a $20 rake lasts for 10 years. In that case, you would budget $2/year ($20 ÷ 10 years = $2/year) for the rake. This might also be the case with a bag of fertilizer. You may buy a 50 pound bag of fertilizer and use half the bag in year one and the other half in year two, so the cost of the fertilizer would be cut in half for your yearly budget. Other materials may be purchased for just one growing season such as pine straw for weed suppression or you may buy only enough seeds for the season.
Labor
A lot of work goes into growing your own vegetables. If you have the time and enjoy gardening then you may choose to charge yourself nothing for your work. However, from a cost analysis perspective you may want to put a value on your work. This will give you a better comparison to buying vegetables.
Budgets
Of course you could create your own budget based on all the costs that go into gardening. But why do that, when it’s already been done for you. The UF/IFAS Costs and Benefits of Vegetable Gardening publication includes a Microsoft Excel Cost Workbook to help answer some of these cost questions. This budget template is customizable, so it’s important that you consider all the costs for your vegetable garden. If you are looking for more detailed crop budgets, there are a lot of North Florida Enterprise Budgets available from UF/IFAS.
by Daniel J. Leonard | Dec 31, 2021
Christmas is among my favorite holidays. The religious significance, music, lights, amazing food, fellowship with family, and giving and receiving gifts all lend something special to the season. However, the tradition that arguably gets the most attention is selecting and putting up a Christmas tree! Those that participate in the festivities and put up a Christmas tree have three options: purchasing an artificial tree, purchasing a real tree, or growing your own.
While I like the convenience of a pre-lit tree as much as anyone, artificial trees don’t do a whole lot for the environment or sustainable US agriculture. They are almost exclusively produced overseas and contain non-biodegradable plastics. Not the best. If you select option two and choose to purchase a real tree, you’ll help support a sustainable US agriculture industry! According to the National Christmas Tree Association, there are ~25-30 million Christmas trees sold annually in the US and 350 million more currently growing on Christmas tree farms waiting their turn! Purchasing real Christmas trees also ensures that the over 100,000 Christmas tree farm workers remain employed, and the 1/3 million acres US Christmas tree farms comprise will remain non-developed “green spaces”!
But for the green-thumbed Christmas enthusiast that’s willing to put in a little time and effort, there is a third choice – growing your very own Christmas tree right at home! In the Panhandle, there are several species, Florida natives and not, that make wonderful Christmas trees and are easy to grow!
Red Cedar makes a fine Florida Christmas tree!
Red Cedar (Juniperus virginiana) – This Florida native is the classic southern evergreen. Growing quickly to the desired heights of 4’-10’, emitting a “Christmas tree smell”, and possessing dark, dense foliage, Red Cedar makes an excellent Christmas tree! Red Cedar performs very well in most soils but does not like wet feet and will not tolerate continuously saturated areas.
Leyland Cypress (x Cupressocyparis leylandii) – A hybrid of Alaskan Cedar and Monterrey Cypress, Leyland Cypress is recognized as one of the most popular Deep South grown Christmas trees for good reason. Leylands grow exceptionally fast, are a desirable forest green color, and have a naturally conical shape! Though not recommended as long-term landscape trees in Florida due to disease susceptibility, Leylands do very well in short Christmas tree rotations.
Thuja ‘Green Giant’ – ‘Green Giant’ is a cultivar of Thuja and is similar in appearance to Leyland Cypress. Though not quite as deep green in color as Leyland, ‘Green Giant’ also grows rapidly (up to 3’-4’ annually), tolerates many soil conditions, and has no serious insect/disease issues.
Arizona Cypress (Cupressus arizonica var. arizonica) – Arizona Cypress is the Christmas tree for those who would normally choose to be different by purchasing a blue, silver, or white artificial tree! Famous for its striking blue/silver foliage, Arizona Cypress is native to the American Southwest but thrives in the drier sandy soils found in many parts of the Panhandle.
Sand Pine (Pinus clausa) – The quintessential “Cracker Christmas Tree”, Sand Pine is native to the deep sandy ridges of Florida. Normally thought of as a scrubby, low-value tree, when shaped a little, the short-needled Sand Pine makes an excellent Christmas tree! Obviously preferring a dry, sandy site but capable of growing nearly anywhere, Sand Pine has no pest or disease issues and grows fast! If you want a true, old-school Florida Christmas tree, Sand Pine is it.
Regardless of the species you choose, implementing the following few maintenance tips and expectations will lend best results:
- Cut/remove J or circling roots before planting.
- Plant just higher than ground level.
- Refill the hole with native soil from the site.
- Regular irrigation for the first several months of their lives is necessary and trees will benefit from supplemental fertilizer applications twice a year (spring and mid-summer).
- Shaping trees each summer with hedge shears to achieve the desired dense, compact shape will allow for a uniform tree with no “holes”.
- Plant several trees per year to ensure a nice tree come December, just in case.
- Florida grown Christmas trees will NOT have the exact look of fir or spruce. Adjust expectations accordingly.
- Most Florida grown Christmas trees do NOT have rigid branches and cannot support heavy ornaments. Again, adjust expectations accordingly.
While Christmas tree species that perform well in the Panhandle will not have the exact look of a classic fir or spruce sourced from the Carolinas, they certainly mimic the look and there is something to be said for walking outside and harvesting your own tree to put presents under! For more information on growing your own Christmas trees or other horticultural topics, contact your local UF/IFAS County Extension office! Happy New Year!
by Daniel J. Leonard | Dec 15, 2021
For many people in the Panhandle, gardening season begins when the weather warms in spring and nurseries start setting out tomato transplants. While I understand the allure of the yummy summer veggies and spring/early summer are the most traditional times to garden, cultivating a winter garden in the Panhandle unlocks many tasty options. Among these cool-season garden veggies is a classic southern staple that is among the easiest and most rewarding of all vegetables to grow, sweet onions!
‘Texas Super Sweet’ Onions almost ready for harvest in a Calhoun County garden. Photo courtesy of Joe Leonard.
Sweet onions are very popular in the culinary world for their mild flavor and soft texture and are among the most widely grown group of onions across the world, but the most famous of them, Vidalia’s, hail from Georgia! Despite its fame, the “Vidalia” onion is actually nothing more than a trademarked name for a specific variety of sweet onion that was bred in Texas (‘Yellow Granex’ and its derivatives), grown in a 20-county region in South Georgia with excellent onion-growing soil, and made famous by excellent marketing from the Vidalia Onion Committee. While they can’t be called Vidalias legally, you can absolutely grow your very own Vidalia type sweet onions at home here in the Florida Panhandle!
Sweet Onions are most easily grown at home if purchased in the fall as “sets”. Sets are small bulbs that have been started, harvested, dried to prevent rotting during storage, and shipped to garden centers ready to be “set” out in home gardens. Sweet onions may also be grown from seed but take much longer and have a lower success rate. When browsing onion set varieties for purchase at garden centers or in seed catalogues, make sure to purchase a short-day “Granex” type like “Texas Super Sweet” or similar. It is critical to remember that sweet onions are classified by how many hours of daylength they require to produce bulbs. The three classifications are Short, Mid, and Long-Day. Since sweet onions require cool weather to develop properly, Floridians must grow short-day varieties to compensate for decreased daylight hours in the winter. In the less hot Northern states, long-day sweet onions are grown in the summer, where they’ll be able to soak up 15-16 hours of daylight. Therefore, for best results in the Panhandle, select ONLY short-day onion varieties.
‘Texas Super Sweet’ Onions that have been harvested and are ready for use! Photo courtesy of Daniel Leonard.
Once you’ve selected your onion sets in the fall, they can be planted in the garden anytime from early October to mid-December. Individual bulbs should be planted about an inch deep in well-drained garden soil with high organic matter content (mushroom compost, composted manure, or other rich organic matter works) and spaced 4-6” between plants and about a foot between rows. Onions in general, and sweet onions in particular, are heavy feeders and require ample nutrition to meet their potential! To meet these fertility needs, I apply a slow-release fertilizer like Osmocote or a Harrell’s product at planting and supplement that with either a quick release granular or liquid fertilizer monthly during the bulb enlargement phase. Sweet onions also have a shallow root system and require frequent watering to develop properly and avoid splits, doubles, and small bulbs. Don’t let your onion bed dry out!
Finally, sweet onions planted in late fall/early winter are normally ready to harvest in April and May. However, rather than relying on a calendar, begin harvesting your onions when the tops start to turn yellow and fall over, this indicates maturity. After harvesting, allow your onions to “cure” with tops and roots still attached for a couple of weeks outside in a shaded, protected area. Once they’ve had an opportunity to “cure”, remove tops and roots and store the cured bulbs in a cool, dry place (a dark pantry in an air-conditioned room or the refrigerator crisper drawer work fine) and use at your convenience!
While they can’t be called Vidalias, sweet onions grown at home are oh so rewarding and very tasty! Provided they are planted in quality soil, receive plenty of water and fertilizer, and are harvested/stored correctly, sweet onions will provide a delicious, home-grown culinary treat throughout the year! For more information about growing onions in the home garden or any other horticultural/agricultural topic, contact us at the UF/IFAS Calhoun County Extension Office. Happy Gardening!
