by Julie McConnell | May 3, 2014
The last week of April 2014 brought with it 10-22 inches of rain across the panhandle in a matter of days. Some areas had immediate flooding and standing water, while others may be in areas at risk of rising rivers and streams. As the water recedes, many people are wondering how all the water will affect their landscapes.
Only time will tell what the long term impact will be, but here are a few things to watch for and what you can do to try to moderate damage.
- Let soils dry out before driving vehicles or other equipment on grassy areas. Even if the water is not visible, if the soil is still saturated, driving lawn equipment or cars may cause ruts.
- Do not leave automatic irrigation systems running on established shrubs, trees, and lawns. If your system is set to run in the early morning hours, you may not think about it being on, check your systems and hold off on adding water until soils dry out and the plants need it.
- Watch for fungus symptoms and treat if needed. Wet plants and cool weather are ideal for some Brown Patch on lawns, be aware and monitor landscapes closely. If disease is suspected, contact your local county extension office for recommendation.
- When mowing, leave a longer leaf blade to compensate for root stress.
- Look at the base of trees and shrubs to make sure silt and sand have not buried the crown or root flare. Also look for erosion of root zone, these areas may need correction. “Salvaging Flood-Damaged Shrubs and Ornamentals.”
- Adjust fertilization as needed; if you recently applied fertilizer it has likely runoff or leached from the site. However, if you suspect fungal disease do not fertilize until disease is managed.
- Stress in turfgrass, for details read “Watch Turf for Flooding Stress”
- You may see new weeds (seeds or segments may have washed or blown into your yard)
- Tree and shrub decline or death read “We Had Plenty of Rain, Why are My Trees Dying?”
- Although this storm was not a hurricane, “Assessing Damage and Restoring Trees After a Hurricane” has helpful information for areas with wind damage
- Nutritional deficiency symptoms in palms may show up 4-5 months from now. “Nutrient Deficiencies of Landscape and Field-grown Palms in Florida.”
- Decreased availability and increased price of sod (flooded fields prevent harvest and increase inputs for disease, weed, and nutrition management)
- Scheduling changes or maintenance adjustments by landscape contractors. Turfgrass and ornamentals will likely need different maintenance applications than in years past to correct issues related to flooding and excess rain.
by Taylor Vandiver | Apr 29, 2014
Now that spring has finally sprung and summer is well on its way, you may find yourself taking a stroll through your landscape and assessing damage done by late cold spells. However, it may not be a frost problem that has your plants looking worse for the wear. They could be experiencing nutritional imbalances which affect overall plant health. Most cases involving nutrition issues in plants can be linked back to the soil. Therefore, if you suspect a problem I suggest testing your soil to ascertain pH and nutrient levels. You can obtain a soil test kit at your local UF IFAS Extension office. Another way to diagnose your plant damage is to visually catalog its symptoms. Symptoms of mobile nutrients, such as nitrogen and phosphorus, tend to reveal themselves on older leaves first. Whereas, immobile nutrient symptoms (i.e. boron and calcium) will show up on newer leaves. These flow charts can help to narrow down which essential element may be lacking in your plant’s diet.
Mobile Nutrient Symptoms.
Immobile Nutrient Symptoms.
by Matthew Orwat | Apr 8, 2014
Powdery mildew on rose bud. Image Credit Matthew Orwat.
Powdery mildew on rose leaf. Image Credit Matthew Orwat.
This spring powdery mildew has been prevalent on many non-resistant cultivars of ornamental plants, particularly rose and crapemyrtle.
Ideal conditions for powdery mildew development, warm days and cool nights followed by rain, have been present for several weeks in Northwest Florida.
This fungus, which looks like powdered sugar and is caused by several different species, appears on new growth and causes distorted and stunted leaf and flower development. It grows in thin layers on the surface of leaves and reproduces by spores.
Mild cases are of little concern, as most plants will grow out of it once environmental conditions change to be less favorable for development of the pathogen. Severe cases can cause distorted growth, leaf drop and flower destruction.
In these cases, fungicide application will protect new growth from this disease. Some lower toxicity fungicides that have been shown to have effectiveness on powdery mildew include neem oil and potassium bicarbonate (otherwise known as Baking Soda).
Sulfur can be used, but cannot be applied when temperatures reach above 90 ° F. Other chemical fungicides, including those containing myclobutanil, or azoxystrobin can be used but products obtained must be labeled for ornamental use. Remember, the label is the law.
Many disease resistant cultivars of rose and crapemyrtle exist, please follow the links provided for more information.
Powdery mildew on rose petiole. Image Credit Matthew Orwat.
Powdery mildew on rose. Image Credit Matthew Orwat.
by Mathews Paret | Mar 25, 2014
Figure 1. Witches’ broom like appearance, abnormal red discoloration of shoots and foliage, excessive thorns, distorted leaves, and deformed buds and flowers are key symptoms for the devastating Rose Rosette Disease
Roses are one of the most popular flowering shrubs in U.S. with a total wholesale value of 194 million U.S. Dollars. Among the major states in U.S., Florida is the fourth largest producer of roses with a total value exceeding 20 million U.S. Dollars. Among the major diseases on roses, Rose Rosette Disease caused by Rose Rosette Virus (RRV), an Emaravirus has been a major problem for roses in many states in the U.S during the last many years. This virus is spread by an eriophyid mite species Phyllocoptes fructiphilus. This disease was not present in Florida until November 2013, when the disease was first discovered and now confirmed in 3 Florida counties, which include one in the Panhandle. On Wednesday March 19, Horticulturists from throughout the South met at the NFREC in Quincy Florida to discuss detection and control measures that might be used to combat this viral disease.
Figure 2. Severe thorn proliferation is another characteristic of rose rosette disease.
The key symptoms for Rose Rosette Disease include witches’ broom, excessive thorns, abnormal red discoloration of shoots and foliage, distorted leaves and deformed buds and flowers (click the link below for symptoms). The diseased plants usually die in 1-3 years. Considering the economic importance of the rose plants, and the highly destructive nature of the Rose rosette virus, research is currently underway by scientists at the University of Florida and the Division of Plant Industry-FDACS to develop early detection methods for the virus and management practices. This project is funded by Florida Nursery Growers and Landscape Association, and the University of Florida, IFAS Dean for Research.
Figure 3. Distorted flower bud; leaf developing from flower bud tissue.
Figure 4. Severe yellowing and stunting of the plant. Infected plants usually die in 1-2 years.
How Home Gardeners and Landscape Professionals Should Respond:
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Routine scouting and early identification. Submit samples for definitive confirmation.
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Destroy infected plants. There is no cure for rose rosette disease. Detection will prompt a quarantine by DPI until cleaned up.
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Eriophyid mite management in early spring is not necessary right now since it has not been found in Florida.
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Note: The Eriophyid mite species described as the vector for RRV is not known to be present in Florida. Thus mite management recommendations are protective in nature.
Further details can be found in the links below.
U-Scout Pest Alert
by Matthew Orwat | Mar 18, 2014
March may seem a little early to worry about fungal diseases, but recent prolonged wet weather and warmer temperatures have made the climate just right for a variety of leaf diseases in the Florida Panhandle. One in particular, Blackspot (Diplocarpon rosae), is particularly problematic for the discerning rose grower. Blackspot is just beginning to be seen this season on non-resistant rose cultivars throughout the central Florida panhandle.
Monsieur Tillier, a rose that shows promise for blackspot resistance, is also part of the Earthkind program. Image Credit Matthew Orwat
Blackspot spores are spread from the canes or leaves of the previous season’s growth by rain or overhead irrigation. To minimize innoculum (black spot spores) remove all leaves from the previous season and any dead leaves at the base of the plant. After the annual pruning in mid to late February, it is a good idea to spray roses with sulfur or copper based fungicidal soap. This helps kill spores that have been laying dormant throughout the winter. Be careful not to spray these products when temperatures rise above 80 ° F. Doing so could burn the plants, although these products will damage tender young growth as well at temperatures below 80 ° F .
Wet, blackspot affected leaves. Image Credit Matthew Orwat
While dormant sprays often allow rose gardeners to get ahead of the disease, the best defense for the home garden is to plant resistant cultivars. There are several old and new resistant cultivars on the market. Some new resistant cultivars of note include Home Run and Knockout. Also, several older cultivars have demonstrated excellent resistance, such as Mrs. B.R. Cant and Spice. The author has been working with several older rose cultivars at the UF / IFAS Washington County Extension demonstration garden that have shown resistance during the last three years. While this demonstration garden is not a scientific study, several roses that have demonstrated some merit include Belinda’s Dream, Monsieur Tillier, Mme. Antoine Mari, Rosette Delizy and Souvenier de la Malmaison. Another resource for information on disease resistant roses is the Texas Earthkind rose program from Texas A&M University. While disease resistance is not always identical in different parts of the county, their recommended list gives the beginning rose gardener a good place to start.
Mrs. B. R. Cant, a tea rose from 1901 has shown very good blackspot resistance at the UF IFAS rose trials in Quincy, FL. Image Credit Matthew Orwat
Several other cultural methods that will prevent spread of this disease among the rose garden include avoiding overhead irrigation, planting in well ventilated areas and proper plant spacing. These techniques attempt to make the garden environment inhospitable for blackspot proliferation.
Regardless if these management techniques are followed, if traditional large, long-stemmed, high maintenance Hybrid Tea roses are desired, most Florida rose gardeners will need to begin a spray schedule to prevent the onslaught of blackspot. Several fungicides are on the market to aid in this process, but remember that they must be used regularly (every 7-14 days) and modes of action must be rotated. This means that different types of fungicide must be rotated so that resistance to a particular fungicide by the blackspot organism does not develop. Below is a table of recommended fungicides for homeowner blackspot control. For more information, please consult the UF IFAS Extension publication P268, Blackspot of Rose.
Fungicide products marketed toward homeowners for control of black spot on roses
|
Active ingredient
|
Fungicide group
|
Trade name
|
|
Copper hydroxide
|
M1
|
Hi-Yield ® Copper |
|
Copper Sulfate
|
M1
|
Bonide® Copper Dust |
|
Copper Octanoate
|
M1
|
Bonide® Liquid Copper, Natural Guard Copper Soap, Ortho® Disease B Gon® Copper Fungicide |
|
Sulfur
|
M2
|
Bonide® Sulfur Dust, Ferti-lome® Dusting Sulfur, Green Light, Hi-Yield® Dusting Wettable Sulphur, Ortho® Bug-B-Gon® Rose & Flower Care |
|
Mancozeb
|
M3
|
Bonide® Mancozeb |
|
Captan
|
M4
|
Bonide® Captan 50WP, Hi-Yield® Captan 50W Fungicide |
|
Chlorothalonil
|
M5
|
Bonide® Fungonil, Ferti-lome® Broad Spectrum, Hi-Yield® Vegetable, Flower, Fruit and Ornamental Fungicide, Monterey, Ortho® Disease B Gon™ Garden Fungicide , Monterey Fruit Tree, Vegetable & Ornamental Fungicide |
|
Myclobutanil
|
3
|
Spectracide Immunox® Multi-Purpose Fungicide |
|
Propiconazole
|
3
|
Ferti-lome® Liquid Systemic Fungicide, Monterey Fungi-Fighter |
|
Tebuconazole
|
3
|
Bayer Advanced™ Disease Control for Roses, Flowers & Shrubs |
|
Tebuconazole + Imidacloprid
|
3 +
|
Bonide® Rose RX Systemic Drench, Feti-lome® 2-N-1 Systemic |
|
Triforine
|
3
|
Ortho® RosePride® Disease Control |
|
Calcium Polysulfide
|
NC
|
Hi-Yield® Lime Sulfur Spray |
|
Neem Oil
|
NC
|
Bonide® RX 3 in 1, Green Light® Neem Concentrate, Green Light® Rose Defense®, Monterey |
|
Acetamiprid + Triticonazole
|
NC + 3
|
Ortho® Bug B Gon® Insect & Disease Control |
|
Acephate + Resmethrin + Triforine
|
NC + NC + 3
|
Ortho® RosePride® Insect, Disease & Mite Control |
| Fungicide Group (FRAC Code): Numbers (1-37) and letters (M) are used to distinguish the fungicidal mode of action groups. All fungicides within the same group (with same number or letter) indicate same active ingredient or similar mode of action. This information must be considered in making decisions about how to manage fungicide resistance. M=Multi-site inhibitors, fungicide resistance is low; NC= not classified. Source: http://www.frac.info/ (Fungicide Resistance Action Committee, FRAC).
Always read a current product label before applying any chemicals.
|
by Blake Thaxton | Nov 25, 2013
Citrus Canker lesions on leaves. Photo Credit: Beth Bolles, UF IFAS Extension – Escambia County
Authors: Blake Thaxton & Mary Derrick, UF/IFAS Extension – Santa Rosa Co. Mikaela Anderson, FDACS Division of Plant Inspection
Citrus canker is a serious disease of citrus trees that was recently confirmed for the first time in southern Santa Rosa County. Canker is caused by the bacterial pathogen Xanthomonas citri subsp. citri. Citrus canker has been a major pest of citrus in south and central Florida. It is economically damaging to the commercial industry and is also problematic to homeowners because it causes premature fruit drop, discolored fruit, and eventually causes the tree to become unproductive.
Canker was first introduced in 1912 into Florida and was declared eradicated in 1933. The disease was found again in the Tampa area on citrus in 1986. It was declared eradicated in 1994, but once again was found in 1995 in Miami. This time, the disease was not successfully eradicated in part because hurricanes made the disease too widespread to control. Despite its prevalence in south and central Florida, this disease has not been known in the Panhandle. The University of Florida and the Florida Department of Agriculture and Consumer Services’ Division of Plant Industry will be assessing the extent of the disease in Santa Rosa County in the coming months.
Lesions growing through the channels formed by the Citrus Leafminer insect. Photo Credit: Beth Bolles, UF IFAS Extension – Escambia County
How might you know if your citrus is infected by canker? One of the best indicators of canker is the presence of lesions, diseased spots, on the upper and lower surfaces of the leaves. The lesions will be raised and have a rough surface and will be surrounded by yellow halos. Similar lesions may be present on the fruit and stems as well.
[important]If you suspect that your citrus trees may have citrus canker please contact the Division of Plant Industry’s Helpline Center at 1-888-397-1517
before taking any action to reduce accidental spread of this disease. [/important]
Lesions formed on the stems. Photo Credit: Beth Bolles, UF IFAS Escambia County Extension
The disease is highly contagious to citrus only and spreads rapidly through wind, rain and via people on their hands, clothes, and tools. Do not transport any plant material that shows symptoms of canker. Decontamination practices should be used when going from one citrus tree to the next. Hand washing with soap and water for 20 seconds or more to eliminate bacterium on the skin should be practiced as well as using alcohol-based hand sanitizer. Pruning tools or other tools that come into contact with citrus should be disinfected by a fresh solution of 1 ounce of household bleach to 1 gallon of water. An old or dirty bleach solution is not able to disinfect because the chemical is no longer active.
[warning]Do Not Move a Plant Infected with Citrus Canker. Please Call your local Extension Office for further instructions[/warning]
For more information on citrus canker:
(The University of Florida IFAS Citrus Canker website provides a photo gallery of disease symptoms & information about the disease)
