by Matthew Orwat | Feb 17, 2022
Citrus red mite leaf damage, red mites may overwinter, but are susceptible to control by dormant oil. Image UF / IFAS HS-806
During cold winter weather, one doesn’t often think about spraying fruit trees and ornamental shrubs for spring insects and diseases. It’s just not on the radar, but it turns out that January and February are the best time to apply dormant sprays to combat insect and disease issues. Many ask, “What are dormant sprays”?
Dormant sprays act on insects or disease pathogens differently. Many insects overwinter on trees and shrubs, either as eggs or immobilized in a protective shell (scale insects). Horticultural oils applied during cool dormant conditions work by smothering the eggs of some insect species or encapsulated scale insects. Since they cannot breathe, they die.
On the other hand, dormant sprays containing copper or sulfur actually kill latent fungal spores that are ready to infect the moment weather warms. They also burn tender young plant tissue, so can only be used when the plant is not actively growing. These preventative sprays can delay disease incidence in early spring and allow for reduction or elimination of regular fungicide applications. The old adage “an ounce of prevention is worth a pound of cure” surely applies to these situations.
Phomopsis leaf and stem symptoms. Dormant fungicide sprays may lessen the severity of this disease.
Credit: N. Flor, UF/IFAS
There are several products on the market for dormant applications.
Dormant oil is a type of horticultural oil, made of refined petroleum products, for application on trees or shrubs when the trees are not actively growing. It has been in use for over 100 years. They are effective in the suppression of scale insects and mites. Care must be used to not apply them when daytime temperatures are above 75 degrees or night temperatures below 28 degrees. Other horticultural oils exist that may be applied during the growing season to control soft-bodied insects, but not during extremely hot weather. Many different brands exist, some are certified organic. They can be purchased at most garden centers, but the best selection is usually found at your independent nursery or farm store.
Cottony Cushion Scale, often controlled by Dormant Horticultural Oil. Image Credit, Matthew Orwat, UF / IFAS Extension
Dormant fungicides can be classified into two groups. Those that contain copper and those that contain sulfur. The most common preventative remedy for fungal disease had been lime-sulfur. It is no longer available in small home garden quantities due to shipping container restrictions, it can be purchased online in larger quantities for use in Florida. When applied to dormant plants, lime sulfur actually works by sanitizing the stem, killing all fungal spores. It cannot be used during the growing season since it burns leafy tissue. Caution must be taken when mixing and loading since, being an acidic product, can burn the skin. Wear chemical resistant gloves when applying (bought at your local hardware store for $4.00-$10.00), safety goggles and follow all label directions carefully since it is caustic and labeled DANGER. Also, never apply lime-sulfur within one month of horticultural oil applications. It should be applied in early to mid February, avoiding hard freezes for the 24 hours around application time. Sulfur based fungicide sprays may also be used instead of Lime-Sulfur as a dormant application.
Dormant copper sprays are effective on both bacterial and fungal pathogens and used primarily on fruit crops for the suppression of many fruit diseases including fire blight, bacterial leaf spot, powdery mildew, downey mildew and anthracnose. There are several different brands of copper fungicide preparations on the market, most nurseries and garden supply centers will have some in stock. Always read the label for proper personal protective equipment and dosage rates, to avoid copper buildup in the soil over time.
For more information, contact your local extension agent or consult these extension publications from: Disease Management Strategies, Florida Blueberry Disease Guide and Pest Control Using Horticultural Oils .
This article was originally published on January 2016, and has been modified to reflect current information.
by Ray Bodrey | Feb 17, 2022
Are you “chomping at the bit” to get started gardening this year, but not sure what you can do at this point? Well, good news, there’s plenty of things that can be done whether landscaping or vegetable gardening is your passion.
“New” potatoes grown in Florida. Photo Credit: C. Hutchinson, UF/IFAS
Temperatures can drop significantly in the Panhandle this month, and with short notice. If you want to enhance your flower beds, be sure to use annual bedding plants that can withstand the chill. Dianthus, pansy, viola and dusty miller are some good suggestions to plant. It’s a good time to plant bulbs too. Dahlias, crinum and agapanthus are good choices this time of year. Be sure to provide adequate mulch and water during this cold weather month. There are plenty of trees and shrubs that are beginning to bloom this time of year also. If you’re like me, your allergies will tell you this too. Red maple and star magnolia, just to name a couple, will soon be in bloom.
As for vegetable gardening, the potato is a good choice for Florida gardens. As Americans, we consume approximately 125 pounds per person a year. Potato farming is done commercially in Florida, but mostly with “new” potatoes. These are the small, rounded immature potatoes that have a thin skin and are perfect for low country boils.
It’s February, so it’s Irish potato planting season. The planting season for this cultivar for the Panhandle is from February 1st to mid-March. Sweet potatoes can be planted beginning in late March through June. A hundred pounds of seed potatoes should yield approximately ten bushels. Buy healthy certified seed potatoes from a garden center. Avoid using table stock potatoes. Often, table stock will not sprout successfully. Store bought potatoes are often treated with sprout inhibitors too. This treatment can cause development issues if used as seed potatoes.
Raised beds, at least 6”, are the best way to grow potatoes. Be sure to fertilize the bed soil mixture and fertilize again down furrows when planting. Irish potatoes require copious amounts of fertilizer. For fertilizer, use a general, complete formulation like 10-10-10. Before planting, be sure to dust the seed potatoes with a fungicide to reduce the chance of decay. Plant seed potatoes 3” in depth, at 12” apart and allow for 36” row spacing.
Please take these gardening tips into consideration this month and the next. Spring is just around the corner. Happy gardening! For more information please contact your local county extension office.
Supporting information for this article can be found in the UF/IFAS EDIS Publications, “ Florida Vegetable Gardening Guide” by Sydney Park Brown, Danielle Treadwell, J. M. Stephens, and Susan Webb : http://edis.ifas.ufl.edu/pdffiles/VH/VH02100.pdf and “Growing Potatoes in the Florida Home Garden”, by Christian T. Christensen, Joel Reyes-Cabrera, Libby R. Rens, Jeffrey E. Pack, Lincoln Zotarelli,Chad Hutchinson, Wendy J. Dahl, Doug Gergela, and James M. White: http://edis.ifas.ufl.edu/pdffiles/HS/HS18300.pdf
Supporting information can also be found on the UF/IFAS website under “Florida Gardening Calendar” by Sydney Park Brown: http://solutionsforyourlife.ufl.edu/lawn_and_garden/calendar/pdfs/February_North.pdf
by Matt Lollar | Feb 10, 2022
Donna Arnold, University of Florida/IFAS Extension – Gadsden County
Donna Arnold is the Small Farm and Residential Horticultural Agent for the Gadsden County since January, 2022. Her main role as an agent is to provide educational programs, related to sustainable agriculture to farmers in Gadsden County north Florida. These programs in small farms and residential horticulture include: best management practices, production, harvesting, marketing, and sustainability issues. In addition, she will provide direction and leadership for the Master Gardener Program also in the County.
Donna holds a Master of Science Degree in Entomology form Florida Agricultural and Mechanical University (FAMU). In her research she examined the prevalence of Solenopsis invicta virus 3 (SINV-3) in fire ant alates collected in north and central Florida. Previously, she was employed to the Oberlin High School Kingston via Ministry of Education Youth and Culture in Jamaica for over 20 years where she was an Agricultural Sciences teacher and the Head of the Agriculture Department. Her job duties involved managing the school tutorial farm and supervision of members in the agriculture department. She also participated in many on the job trainings and earned certificates in the field of Agriculture and was a part of the National 4-H clubs.
Donna Arnold in Beekeeper Jacket
Her experience in Agriculture began at an early age; she was raised in a small farming community in East Rural St Andrew, nestled in the blue mountain regions of Jamaica. Farming was the main source of income there – Coffee and vegetable crops predominately grown. Since agriculture was embedded in her from a tender age, this act as a catalyst to propelled her to learn more about the pedagogical aspects. Donna’s formal agricultural experience began at Elim Agricultural School, now known as Sydney Pagan Agricultural School, where she was awarded a certificate in General Agriculture.
She later worked in extension with Rural Agricultural Development Authority under the Ministry of Agriculture. During her tenure she saw the need to upgrade educationally to better served her farmers in rural communities, therefore, she pursued an Associate of Science degree in Agriculture (ASc.), and a Bachelor of Technology in Food System Management and Agriculture Production (BTECH) respectively, at the College of Agricultural Science and Education (CASE). After which, she pursued a Diploma in Teacher Education at the Short wood Teachers College.
With the knowledge and skills garnered this led to her understanding that agriculture plays a vital role in food security because she believes a country is not independent until it can feed itself. It was always Donna’s intention to continue working in Agricultural extension, there she believes she can make a positive impact on farmers lives since they are the drivers of food production.
During her spear time one can find Donna tending plants, working with honey bee research and, watching home and garden television series. Her motto is “attitude is a little thing that makes a big difference” by Winston Churchill
by Molly Jameson | Feb 10, 2022
Join us via Zoom on Saturday, February 12, for our Leon County Seed Library Virtual Workshop. Graphic by Molly Jameson.
Believe it or not, spring is right around the corner! For gardeners, this is the time to start thinking about our spring season garden plan and starting seeds. Many spring vegetables, such as tomatoes, benefit from an early start indoors or in a greenhouse, planted in containers. This gives them a greater chance to avoid the intense heat of summer and beat many insect and disease life cycles.
Need seeds to start your garden? Well, if you live in Leon County, you are in luck. Starting Saturday, February 12, 2022, residents of Leon County can “check out” up to three sample seed packets per month with their library card as part of Leon County’s Seed Library Program. The vegetable seeds can be checked out from any of the seven library branch locations. Leon County residents can apply for a library card online at the LeRoy Collins Leon County Public Library online card application page (https://lcpl.ent.sirsi.net/custom/web/registration/).
Here are the vegetable seed varieties that will be available starting February 12:
- Mammolo Basil. Mammolo basil has an Italian aroma and a bushy, compact growth habit that is great for containers.
- Maxibel Haricot Vert Beans. Maxibel Haricot Vert produces prolific beans with long, slender pods and tender texture.
- Natsu Fushinari Cucumbers. Natsu Fushinari is a deep green Japanese-type of cucumber with eight-inch fruit and glossy skin. It has resistance to diseases in high heat.
- Little Fingers Eggplant. Little Fingers eggplant produces clusters of tender, long, deep purple fruit that can be harvested small or large.
- Pinkeye Purple Hull Southern Peas. Pinkeye Purple Hull Southern is a semi-bushy, early-season pea that produces prolific dark purple pods. It has resistance to many diseases.
- Bull Nose Peppers. Bull Nose is an old pepper variety, dating back to the mid-to-late 1800s, and has medium to large, sweet fruit that is great for cooking or salads.
- New Zealand Spinach-like Greens. New Zealand spinach is not a true spinach, but it loves the heat and produces succulent leaves that are excellent cooked or fresh in sandwiches.
- White Scallop Squash. White Scallop is a high-yielding Native American heirloom that produces scallop-shaped fruit great for frying or baking.
- Homestead 24 Tomatoes. Homestead 24 is a semi-determinate tomato that has medium to large red fruit developed for hot, humid climates, making it great for Florida gardens.
- Amy’s Sugar Gem Tomatoes. Amy’s Sugar Gem grows tall, vigorous vines and produces sweet, large red cherry tomatoes.
- Moon and Stars Watermelon. Resembling the night’s sky, Moon and Stars watermelon has a dark green rind with bright yellow spots. It has speckled yellow leaves and seedy, but very sweet, bright red flesh.
Whether you are located in Leon County or not, everyone is welcome to join us Saturday, February 12, from 10:00 a.m. to 12:00 p.m., for our Leon County Seed Library Virtual Workshop. Via Zoom, agents with UF/IFAS Extension Leon County will discuss spring vegetable gardening techniques and healthy eating. There will also be a live cooking demonstration showing how to prepare healthy meals and snacks at home, featuring vegetables available in the Spring 2022 Seed Library Program.
For more information about the Leon County Seed Library Virtual Workshop, please visit our Eventbrite page: https://seedlibraryworkshop2022.eventbrite.com. There is no cost to attend the workshop, but registration is required.
Happy spring gardening!
by Daniel J. Leonard | Feb 10, 2022
For being in a place known as the Sunshine State, the Panhandle has been mighty cold and dreary to start 2022! With all the recent bitterly cold weather that’s rolled through our neck of the woods over the last month or so, you may be asking yourself “Is this just a typical Panhandle winter or has it been colder than normal and what is the impact of freezing weather on my fruit trees?” The answer might surprise you!
The easiest way to measure cold and its impact on plants is through a unit of measurement known as a “chill hour”. In its simplest iteration, a chill hour is an hour of time during which the thermometer dips below 45 degrees F. These “chilling hours” are vital to agriculture and our native ecosystems because many plants, especially those that produce fruit like pears, blueberries, peaches, and even citrus, require a certain amount of chill to enter dormancy and develop flower buds for the following spring. All fruit trees have a minimum chilling requirement to initiate flowering depending on variety and too few chilling hours equals poor to no fruit the following year. Too little cold can be just as harmful as too much!
Blueberry beginning to flower after receiving adequate chill hours. Photo courtesy of Daniel Leonard.
Now that we know about chilling hours, the question remains, is this a normal winter or has it been colder than normal? The answer is neither. Based on historical average data from the UF/IFAS weather station in Marianna (a central location in the Panhandle and a good proxy for your local temperatures), as cold as we’ve been in January and early February, we’re still lagging the historical average with respect to chilling hours, and therefore to total cold temperatures. As of February 6th, 512 chill hours had been recorded this winter. This seems like a lot until you check and see that we had 554 chill hours on the same day last year and the historic average is more than 750! Though January and February have indeed been cold this year, the chill hour graph indicates that over the last few years it’s taken longer into the calendar to achieve our first chill hour and that cold weather isn’t pushing as far into spring as it historically has.
There are many potential explanations for the warming trend in the Panhandle but regardless of your preferred theory, backyard fruit growers need to adapt to deal with the change in chill. The primary way to combat fewer chill hours is to evaluate your current fruiting plants and think about replacing high-chill varieties that no longer produce well with lower-chill varieties. If you know the variety you have, look up the number of chill hours that variety requires. If it’s an older variety that requires near the historical chill average or more, you may consider replacing it with a newer variety that requires fewer chilling hours. For example, the popular old blueberry variety ‘TifBlue’ requires 600-700 chilling hours. For most of the previous decade, we have either just barely or not reached that many chill hours, leading to a low fruit set. Replacing ‘TifBlue’ with a newer, lower chill variety like ‘Powderblue’ will probably increase your blueberry production. If you don’t know what variety of fruit tree or shrub you have, just observe the flowering period over the next spring or two. If it doesn’t flower at all or flowers sporadically and you don’t make a good fruit yield, a high chill requirement very likely could be to blame and replacing it could enhance production!
Though we’ve had an intensely cold start to 2022, if current trends continue, this wintry weather will most likely play out before we reach historic averages. That doesn’t mean you can’t grow plenty of backyard fruit, it just requires adapting to the times with lower chill varieties! To keep up with chill hour accumulation, visit http://agroclimate.org/tools/chill-hours-calculator and if you have any questions about fruiting plant variety selection, chilling hours and their effect on plants, or any other horticultural topic, contact your local UF/IFAS County Extension office! Stay warm and happy gardening!
