Sweet Viburnum (Viburnum odoratissimum) is thought of as being an ironclad landscape shrub, generally a rapid, healthy grower free of insects and disease. However, this spring, many Sweet Viburnum specimens across the Panhandle have experienced varying degrees of dieback, from individual shoots to entire sections of shrubs, caused by the fungal pathogen Botryosphaeria – commonly known as Bot Rot.
Bot Rot almost always appears after some kind of major stress event that impacts susceptible plants – drought, pruning wounds, nutritional deficiencies, or another environmental stress. We haven’t been afflicted lately with any serious drought conditions and the disease occurrences are too widespread to have been a result of isolated pruning or poor plant nutrition. However, the Panhandle did experience a major environmental event around Christmas 2022 that was plenty stressful for landscape plants, a weeklong Arctic blast of extreme cold. This abrupt hard freeze event in an otherwise mild winter is my best guess for what brought about the increased incidence of Botryosphaeria we have experienced this spring.
The Botryosphaeria fungus enters plants via wounds – in this case one probably caused by cold – and begins destroying the plant’s vascular system in the area. As the pathogen progresses, it eventually causes sunken cankers to appear, girdles the affected branch, and cuts off “circulation” in that stem. The first symptom of Bot Rot that gardeners notice is shoots rapidly wilting and exhibiting a blighted appearance, with brown, dead leaves holding onto affected limbs. Unfortunately, dieback isn’t always limited to individual shoots and can spread back into plants to eventually encompass whole branches. Entire plants dying from Bot Rot infection is not uncommon.
While there aren’t any fungicides that are effective in controlling or preventing Bot Rot, gardeners can arrest its spread by pruning out infected branches. To completely rid the plant of the fungus, make sure to prune 4” or so below the last infected plant tissue (symptomatic tissue will appear dark and discolored; healthy tissue will appear light and greenish). After pruning each affected plant, it is important to sanitize pruning equipment with either a 10% bleach solution or 70%+ isopropyl alcohol to prevent spreading pathogens to other healthy plants! Plants that have been irreparably disfigured by Bot Rot or outright killed may be pulled and discarded offsite.
While this year’s Bot Rot infestation has been extremely frustrating and similar future freeze events can’t be ruled out, gardeners should not give up on Sweet Viburnum, an excellent specimen or screening shrub. Keeping plants healthy with proper pruning, good fertility, and adequate irrigation is the best defense to ward off future infection when we experience harsh environmental conditions! For more information on Bot Rot, Sweet Viburnum, or any other horticultural topic, contact your local UF/IFAS County Extension Office! Happy Gardening.
Would you like to make money off your land? Are you looking to diversify your current plans on your property? Jackson County is hosting a fruit and vegetable meeting on January 26, 2023, and this just may be the perfect way to start off your new year!
When thinking about what it means to be successful in planting your garden or having fruit trees, often the first thing that comes to mind is a healthy quality crop. This starts with the health of your soil. We will have two specialists that cover soil health and the benefit of adding cover crops to your rotation during the off season. The second thing that might come to mind when wanting to be successful is how to start? how much time do I have to devote to gardening? and how much do I want to do? This meeting will also have a specialist coming to Marianna to cover how to get started on a property with a specialty crop. Even though this information may be geared towards new farmers, it could also be very useful to new land owners and community residents just wanting to do more on their property. You may find that you have so much extra produce that you want to have a little fruit stand!
There will also be a session on the importance of drip irrigation, fertigation and how to implement these practices. Drip irrigation will not only save you money in the long run with the use of less water, but it is also much better for overall plant health by reducing pest and disease problems. Fertigation is the process of adding soil amendments, water amendments and other water-soluble products into an irrigation system. This process can be both beneficial to the plants and cut back on the time it would take to fertilize by hand.
The next session on specialty vegetable and fruit crops will teach about the various exciting specialty crop opportunities in the Tri-State area such as artichokes, blackberries, Seminole pumpkins, and more. Finally, the meeting will also cover cucurbit disease updates and will be extremely useful if you already have a field or garden of watermelons, cucumbers, or squash! Come with questions! CEUs will be offered as well if you are a homeowner that holds a pesticide license.
While, the audience for this conference is primarily small to medium sized, diversified cucurbit and vegetable producers in the tri-state region including the counties in the Panhandle, Alabama, and Georgia, the residential community is welcome to attend and will truly benefit with learning about soil health, cover crops, fertigation, drip irrigation, and specialty crops. The conference will be held at the Jackson County Extension Office in the Peanut Hall. We are planning a full morning with educational sessions and lunch to follow.
This meeting will be $5 at the door and pre-registration is highly encouraged. Please call our office at 850-482-9620 to reserve your seat and if you have any questions.
Tri-State Fruit and Vegetable Meeting
Thursday, January 26, 2023, 8:00 am- 1:00 pm at the Jackson County Agriculture Offices Auditorium, 2741 Penn Ave., Marianna.
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 https://edis.ifas.ufl.edu/publication/PP323 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 https://edis.ifas.ufl.edu/publication/PP323 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.
2022 has been a good tomato growing year for many Panhandle gardeners, myself included. It would have been difficult to have better climatic conditions to aid a terrific tomato harvest. After enduring a late frost just before Easter, the Panhandle then experienced two mild months in April and May that combined with nearly a month of dry weather during fruit development to deliver an excellent fruit set season with minimal disease and insect pressure. However, despite the favorable growing conditions, I have talked with several gardeners that once again struggled to yield a good crop of fresh garden tomatoes. Why is that? With the Panhandle tomato home gardening season nearing its conclusion, now is a perfect time to revisit 3 of the most common mistakes that prevent an excellent harvest!
Not Starting Early – Since Memorial Day, the rain and heat have really ramped up. These hot, wet conditions are perfect for developing tomato plant problems like fungal and bacterial diseases, not to mention the fact that tomato plants will stop setting fruit once nighttime temperatures rise above 75 F. While spraying fungicides preventatively can certainly help decrease disease incidence, the absolute best thing a gardener can do is try to get ahead of the disease-bringing heat and humidity by starting plants early when more favorable growing conditions prevail. So, what is early? I try to have tomato transplants in the ground by March 15 or soon after*. If you plan to grow plants from seed, they should be started indoors mid-January for planting outdoors in mid-March. Most tomato varieties take between 60 and 80 days to mature after planting, so a mid-March planting date normally yields harvestable tomatoes by the middle of May, comfortably beating the June disease deadline. *Planting early means protecting plants from occasional late frosts. Be prepared!
Not Scouting Your Plants – Pest and disease problems are a lot easier to manage if caught early and the best way to do that is to spend time with your plants. If you scout (just walking by and giving plants a short inspection) daily, you’ll learn what tomato plants and the beneficial insects that hang around all the time are supposed to look like an and be able to spot abnormalities and bad bugs when they occur. While tomato diseases and pest outbreaks can certainly cause a lot of damage in a short amount of time, they don’t reach disastrous levels immediately – be vigilant and catch them early!
Not Fertilizing and Watering Correctly – It takes a lot of energy for a tomato plant to grow a nice, bushy plant AND yield an abundance of America’s favorite vegetable (or fruit, depending on who you ask). To produce that necessary energy, gardeners must ensure plants receive adequate nutrition and water. Here’s my general prescription. At planting, apply a general purpose, slow-release fertilizer according to the label rate (for example, Osmocote, Harrell’s, or similar) and gypsum (a calcium supplement that helps prevent blossom end rot) at one pound per hundred square feet of garden. Then, supplement later in the season with a quick-release general purpose fertilizer sufficient to drive growth and fruit development. Watering is more of an ongoing concern. For the first couple of weeks of the tomato plant’s life, you can get by with watering once a day or every other day. As the plants get larger and the days get hotter however, watering twice daily is often needed to prevent wilting down in the heat of the day. Allowing tomato plants to wilt, even for a little while, is an excellent way to encourage blossom end rot and a subpar harvest!
When tomato season rolls around in 2023, remember to start early, scout often, and water and fertilize correctly. Follow those few tips and you’ll be well on your way to a great harvest in 2023! For more information about growing tomatoes or any other horticultural or agricultural topic, contact us at the UF/IFAS Calhoun County Extension Office at 850-674-8323 or email email@example.com. Happy Gardening!
As the temperatures warm into the 70’s and the rain chance remains good, keep an eye open for disease in your lawn. Large patch disease is common in turfgrass this time of the year. It is caused by the fungus Rhizoctonia solani. The fungus is present in the soil and thatch layer year-round. When the temperatures rise into the 60’s and 70’s it begins to spread. Large patch thrives under these conditions, especially when the soil is wet. With frequent showers the disease spreads quickly. The first symptom of large patch is circular, discolored areas within the lawn. The outer borders of the patches are orange to yellowish in color. In the center of the circle there are grass blades trying to green up again. They are usually unsuccessful, resulting in odd-shaped patches of dying grass that begin to connect to each other. A simple field diagnostic techniques to confirm large patch disease is to pull on the diseased grass shoots near the edge of the circle. The blades will come loose from the stolon easily. At the base of the leaves the stem and sheaths will appear dark brown and rotten. Yes, it is large patch. If the weather gets colder or hotter very quickly, the disease will go back into dormancy. Looking at the long range temperature predictions, cool night and warm days are likely to continue for awhile. So, start looking for a fungicide or two or contact your pest control service. However, remember fungicides don’t cure existing problems. They are utilized as a protectant for the unaffected portions of the grass. When favorable conditions are present, the turf should be sprayed in order to keep the fungus from penetrating the grass blades. Repeat applications will be needed for as long as the weather is cool and wet. Check the product label for the correct intervals. Several cultural practices promote large patch infection including over-fertilization, over-irrigation, low mowing height, poor drainage and excess thatch. This spring after the grass has greened-up on its own is a good time to look at these factors and make corrections. Keep a close eye because as soon as the temperatures drop again in the fall, large patch can reappear if the corrections were not complete. For more information: https://edis.ifas.ufl.edu/lh044
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.
A spotted Japanese Persimmon leaf, Image Credit: Matthew Orwat
In gardening, brown or black spotted leaves are most often an indicator of disease problems or growth issues. This causes us to worry and seek answers as to why this is occurring. This is good since the first step in solving a plant growth or disease issue is diagnosis.
During Fall, the presence of brown or black spots on leaves of shade and fruit trees is usually not cause for alarm, as it might be in the spring or summer. Certain shade trees such as Southern Magnolia, Japanese Magnolia, various maple, persimmon and oak in the Red Oak group show substantial brown and black leaf spotting as Fall arrives. This is due to the fact that these leaves have been attacked by fungal pathogens and insects since Spring and resistance to damage has broken down over time. As Fall progresses, these leaves will senesce (purposeful deterioration due to age, such as at end of season) and fall to the ground. Therefore, this ugly spotting is part of natural seasonal leaf decomposition in deciduous trees.
If you happen to live in or near Washington County, we are launching our Second Mondays Free Plant Clinic. Staffed by knowledgeable and friendly UF / IFAS Master Gardener volunteers and your County Extension Agent, we will be available every second Monday of the month from 10am to 2pm at the Washington County Ag Center, which houses the UF / IFAS Extension Office. We will be located in the Master Gardener Volunteer Library which is just left of the central auditorium double doors. The launch date of this plant clinic is Monday, October 11th. See you then!