As homeowners, we do value our trees and no one wants to lose a shade tree especially on the house’s south side in Florida. On a recent site visit, a hickory tree had multiple concerns. Upon closer inspection, the tree had a bacterial infection about 30” off the ground with a smelly, black-brown ooze seeping forth. The leaf canopy was riddled with beetle holes and leaf margins were chewed by caterpillars. When leaves were viewed under the microscope, thrips (insects) and spider mites were found running around. The biggest homeowner cosmetic concern arose from hickory anthracnose (fungus) and upon closer inspection found the leaves to have hickory midge fly galls. The obvious question is should the tree come down? I’ll have you read the whole article before giving you the answer.
Each hickory gall is approximately 3/16″ wide.
Hickory anthracnose or leaf spot as seen in the banner photo is caused by a fungal infection during the wet summer months in Florida. The homeowner can usually recognize the disease by the large reddish brown spots on the upper leaf surface (sending a sample to the NFREC Plant Pathology Lab will confirm the diagnosis) and brownish spots with no formal shape on the bottom. Be sure to rake and remove all leaves to prevent your disease from overwintering close to the tree thus reducing infection next year.
A hickory gall has been cut in half to show the leaf tissue.
The fungus can be lessened by good cultural practices and appropriate fungicidal applications. Please remember it is best left to professionals when spraying a large tree. This alone is not cause to remove your tree.
Hickory gall is caused by the hickory midge fly, an insect that lays eggs in the leaf tissue. The plant responds by building up tissue around each egg almost like the oyster when forming a pearl.
As the gall tissue grows, eggs hatch and larva start to feed on this tissue. The larva will continue to
The larva has eaten all soft material inside the gall and is ready to pupate.
feed until it is ready to pupate within the gall. After forming a pupa, the midge fly will eventually emerge as an adult and females will continue to lay eggs on other leaves. The galls are more of a cosmetic damage and because your hickory leaves will fall from the tree as winter comes, the galls will normally not cause enough damage to worry about each year. Once again good cultural practices and disposal of each year’s leaves will reduce the gall numbers next year.
In a large tree with many leaves, foliar feeding by beetles and caterpillars do cause damage though the leaves will still produce enough food (photosynthesis) to keep the tree alive. Most of us never climb our trees to look at leaves to see the small insects/mites and there are more than enough leaves to maintain tree health.
The biggest concern during my site visit was their tree’s bacterial infection. A knife blade was pushed into the wound area and went in less than 1/4″. The homeowner was instructed to look at bactericide applications. In the end, this hickory tree with so many problems is still shading the home and helping cool the house. It is still giving refuge to wildlife and beneficial insects. When in doubt give our trees the benefit and keep them in place. Remember your local Extension agent is set up to make site visits and saving a tree is time well spent.
The lawn is a source of pride for most and anything out of the ordinary causes alarm. Now image finding something that looks like lumpy green jelly in your turfgrass and it doesn’t go away. You try raking it, spraying it, covering it, and it still comes back time and time again. One of the things we see in late spring/early summer turf is a reemergence of cyanobacteria (Nostoc), sometimes confused with algae because of green coloring and this remains all summer long.
Dehydrated cyanobacteria in a centipedegrass lawn.
Unlike normal bacteria that needs a food source, cyanobacteria contains chlorophyll and produces its own food source through photosynthesis which allows it to grow on bare sandy soils, fabric mats, concrete sidewalks, plastic, and yes even your lawn. Besides the green pigment, it also produces a blue pigment and is why we call it cyanobacteria which means blue-green bacteria. In addition to photosynthesis, cyanobacteria can also fix nitrogen, and are believed to produce cyanotoxins and allelopathic compounds which can affect plant growth around them.
Cyanobacteria are considered one of earth’s oldest organism and they have tremendous survival capabilities. They can dry out completely, be flat, flaky, black-green dried particles in your lawn and once rehydrated, spring back to life. If you happen to notice it spreading throughout your yard, remember that pieces of the organism can stick to your wet shoes or lawnmower tires and be transported unintentionally.
The question then becomes how to control the cyanobacteria and reclaim your turfgrass. The first solution is to have a healthy lawn. Cyanobacteria likes poorly-drained compacted soils. This same condition is unfavorable to turf growth and why you end up with bare spots and establishment. Reduce soil compaction by using a core aerator, and then adding organic matter. This will increase drainage, gas exchange, and encourage microorganism populations which I like to call soil pets. Spike aerators only push the soil particles aside and don’t really loosen as well. Try to reduce low lying areas in the lawn where water sits after rainfall and irrigation. You might have to till and reestablish those areas of the yard.
The same cyanobacteria pictured above 24 hours after being rehydrated in a petri dish of standing water.
Controlling the amount of water Mother Nature gives us and humidity levels during summer is not possible, but you can control your irrigation whether it be automatic (sprinkler system) or hand-watered. During the rainy season, you should be able to get by with only rainfall and shut off your system. If needed during extended dry weeks, it is easy enough to turn the system back on. It is thought that cyanobacteria likes phosphorus which is another reason to use little to no phosphorus in your lawn fertilizers.
As you begin to rid your lawn of cyanobacteria, remember when fully hydrated it forms a slippery surface so be careful walking on it. Cultural practices will be more effective in controlling the spread versus using chemical methods. Cultural solutions are safer for your lawn, yard and all of the wildlife that visits. If you need help with your cyanobacteria, please contact your local Extension office and we are always happy to assist.
A special thanks to Dr. Bryan Unruh, UF/IFAS for his assistance in identifying the cyanobacteria.
For additional information, please read the sources listed below.
The weather is warmer and plans and planting for spring vegetable gardens are in full swing. Last week many vegetable gardening topics were addressed in our Gardening in the Panhandle LIVE program. Here are all the links for all the topics we discussed. A recording of last week’s webinar can be found at: https://youtu.be/oJRM3g4lM78
Home grown Squash. Gardening, vegetables. UF/IFAS Photo by Tom Wright.
Our moderators talked about some of their favorite tomato varieties. Josh Freeman is partial to Amelia, a good slicing tomato. Matt Lollar shared some of the best tomato varieties for sauce: Plum/Roma types like BHN 685, Daytona, Mariana, Picus, Supremo and Tachi. For cherry tomatoes, Sheila Dunning recommended Sweet 100 and Juliette.
Whatever variety you choose, Josh says to pick when it starts changing color at the blossom end and bring it indoors to ripen away from pests.
If the beneficials are not numerous enough to control your pests, maybe a natural approach to pest control can help. Natural Products for Managing Landscape and Garden Pests in Florida: https://edis.ifas.ufl.edu/in197
Tomatoes ripening on the vine – Image Credit Matthew Orwat UF/IFAS Extension
It is late-February, so the spring growing season is just around the corner. Now is the time to be thinking about which tasty tomatoes you want to plant in your home garden! Although tomatoes are a favorite kitchen staple, they prove challenging to grow in the Florida Panhandle climate.
While many tomato diseases can kill plants, damage fruit, and reduce yields, genetic resistance or tolerance to select diseases exist. The following are three of the most common diseases and viruses home gardeners face, for which resistant and tolerant varieties exist.
Tomato spotted wilt affects tomatoes, and numerous other vegetables, ornamentals, field crops and weeds. The disease can cause significant yield losses of tomato. Image Credit UF/IFAS Plant Pathology UScout Site
Tomato Spotted Wilt (TSW) is a viral disease which is transmitted by thrips, a species of insect that is very small and not always visible when checking the garden for insect pests. They love to feed on the sugary juices of the tomato flowers, and while feeding, they have the opportunity to transmit the virus through their piercing and sucking mouth parts. Lots of different symptoms may occur with TSW. Initially growers will notice light or dark brown spots on leaves of affected tomatoes, next wilting or stunting will occur, along with brown or purple streaks on the stems. Finally, fruit will exhibit unsightly brown rings throughout. The good news is that home gardeners can get a head start on this disease by planting resistant cultivars. When shopping for seed or transplants, growers should look for plants listed with the codes TSW or TSWV, because these have demonstrated resistance to Tomato Spotted Wilt Virus.
Another viral disease often found in the tomato garden is Tomato Yellow Leaf Curl (TYLC) Virus. TYLC first appeared in Miami in 1997 and was brought to Florida by infected whiteflies. Much like TSW, TYLC is spread from plant to plant by feeding whiteflies. As the name indicates, TYLC symptoms include curled leaves and stunted growth. Infected plants produce little to no fruit. Strategies to reduce the possibility of virus transmission to the garden include reducing the population of weedy plants, which may harbor whiteflies. Fortunately, resistant cultivars are available in plant catalogs, and are denoted by TYLC to indicate resistance.
Spread of TYLC is by the feeding of TYLCV infected adult whiteflies. Mechanical or seed transmission is not known to occur. Upward curling and yellowing of the leaves is an early symptom. Credit: UF/IFAS Plant Pathology UScout Site
Blighting of leaves and wilting of part or entire plant can expose fruits to sunscalding thereby further affecting yield of affected plants in production. Credit: UF/IFAS Plant Pathology UScout Site
Fusarium Wilt is one of the oldest diseases to affect tomatoes in the state of Florida and is caused by the fungal pathogen Fusarium oxysporum f.sp. lycopersici races 1, 2, or 3. This pathogen is often present in regional soils and moved by wind. Once it enters the roots of tomato plants, fusarium wilt proliferates and clogs the vascular system, much like a clog in the plumbing of a building. Thus, the primary symptom is the wilting of the plant, which will first be noticeable on hot days, despite adequate irritation. Once infected, there is no cure, and infected plants should be removed and destroyed to stop the spread. The good news is that resistant cultivars are available to the various fusarium races. They are usually denoted as F-R 1, 2, or 3 in seed catalogs. Additionally, look for plants labeled VFN. These cultivars are resistant to a different kind of wilt, called verticillium, as well as fusarium and nematodes.
Fortunately, the UF / IFAS publication “Tomato Varieties for Florida—Florida “Red Rounds,” Plums, Cherries, Grapes, and Heirlooms” by Monica Ozores-Hampton and Gene McAvoy has provided us with a handy chart of tomato varieties with disease resistance. Codes in the columns indicate disease resistance to specific pathogens. While there is no single tomato variety resistant to all possible disease pathogens, planting different varieties with several different types of resistance will allow growers to hedge against attack by a number of potential disease problems. Some of the more common disease resistant tomato varieties planted in this area are ‘Quincy’, ‘Bella Rosa’, ‘Amelia’, ‘Tasti-Lee’, ‘BHN 602’, and ‘Volante’.
We are back with new topics and guest speakers for 2021! All sessions are Thursdays at noon CDT or 1:00 p.m. EDT.
There are two ways to join the Gardening in the Panhandle LIVE! webinars:
1. Facebook Live – Follow us on Facebook and follow individual webinar Events.
2. Zoom Webinar – Pre-registration is required for Zoom. Users must have an authenticated account (free at Zoom Link). Be sure you have security settings up to date to prevent connection delays. Links to Zoom registration will be added to the topic one week before the webinar and a closed captioned recorded link to YouTube will be available approximately one week after the program. (Underlined words have active links!)