by Mary Salinas | Apr 28, 2015
Fleshy distortions are appearing on some azaleas this time of year. What is responsible for this? A fungus, Exobasidium vaccinia, likes our cool, wet spring weather and infects azalea leaves and flower petals. This disease likes a cool, wet, shady and protected environment.
Azalea gall. Photo credit: Mary Derrick, UF/IFAS Extension.
The infection causes the plant to form large, fleshy, distorted tissues known as galls. The galls produce a white powdery coating that is capable of producing more spores that will continue to cause new infections if left on the bush. The gall will eventually turn dry and brown and fall to the ground. Sometimes there are only a few leaves infected or there may be quite a few on a bush.
Not to worry – this is not likely to cause significant harm to your azalea. The best plan of action is to remove the galls as soon as possible and dispose of them in the trash or burn them to prevent reinfection of your plants. Avoid any irrigation that sprays water onto the leaf surfaces as the moisture creates a favorable environment for disease. Once you see this gall forming, there is no chemical control that is effective.
For more information on caring for your azalea:
Azaleas at a Glance
by Blake Thaxton | Apr 21, 2015
With the over abundance of rainfall the western panhandle has seen in recent weeks, tomato gardeners need to be aware of foliar diseases that could appear. Tomato leaves are an ideal host when moisture is present on the leaf surface. There are several of these diseases that, if not managed, can destroy the garden.
Early Blight
Advanced symptoms of Early Blight (Photo Credit: UF/IFAS U-Scout website)
Early Blight is a fungal disease that can affect tomato leaves and fruit. The disease is most prominent when temperatures are 80°F and excess moisture is present from rain or irrigation. The most classic system is the presence of leaf lesions that are approximately 1/2 inch in diameter.
Bacterial Spot
Bacterial Spot on a Tomato leaf (Photo Credit: Hank Dankers, From U-Scout)
Bacterial Spot can also cause problems for Florida tomato gardeners in rainy and high temperature periods. Generally the symptoms are darkened circular lesions on the leaves and fruit. Sometimes bacterial spot can be confused with other leaf lesion diseases. The bacterial spot will ooze when cut where as fungal type lesions will not.
How to prevent foliar diseases in tomato:
- Always start with disease free seed and transplants.
- Irrigate early in the day to minimize the time the leaves stay wet. Use drip irrigation when possible.
- Remove blighted leaves when the garden is dry. This technique should not be relied on exclusively.
- Remove and destroy crop residue at the end of the growing season. If not removed, it can become a breeding ground for disease next year.
- Rotate to different plant families that are not affected by the same diseases.
- Spray protective fungicides such as Mancozeb, Copper, and Chlorothalonil (for example sold as Daconil) when the conditions are right for disease (higher temperatures, excessive moisture, and rainfall).
If you have questions about these diseases or other tomato diseases, please comment below or call your local UF/IFAS Extension Agent.
by Beth Bolles | Apr 7, 2015
One of the most commonly used shrubs in landscapes is the Indian hawthorn, Rhapheolepsis indica. Although not native to Florida, it can be a very attractive shrub when used properly in landscapes. Plants offer spring flowers in pinks and whites followed by berries that are a food source for birds.
Indian hawthorn as a single planting can be attractive.
Indian hawthorn plants in landscapes are susceptible to a couple of pests that create unattractive and unhealthy plants. A leaf spot fungus called Entomosporium leaf spot easily spreads from infected plants through irrigation and rainfall leading to leaf discoloration, leaf drop, and dieback of limbs. Scale insects can also be common on leaves causing yellowing and dieback. The fungal problem is difficult to manage on heavily infected plants but the scale can be managed with a low toxicity pesticide choice such as a horticulture oil.
A heavy infection of leaf spot fungi is often too difficult to manage when plants are routinely irrigated.
Most often the problems on Indian hawthorn, especially fungal, are the result of poor management. This shrub likes sun, well-drained soil, and no overhead irrigation. Once established, plants should need little supplemental irrigation and water should only be applied to the base of plants. Since plants normally form a rounded mound, there is also little need for pruning if planted in a correct spot and spaced appropriately when planting. Most landscape installations of Indian hawthorn space plants based on the gallon pot size and not the mature size of the plant which is about 3-5 feet in height and spread.
Indian hawthorn can still be a good selection for homeowners. Buy healthy plants without any signs of spots on leaves and don’t plant a monoculture of these plants in the landscape. If one plant does have serious pest issue it is easier to either treat or remove one plant versus a mass planting.
by Julie McConnell | Feb 10, 2015
When talking about pest issues in the landscape, green industry professionals often refer to IPM or Integrated Pest Management.
Chinch bug damage to St. Augustinegrass. Photo: Julie McConnell, UF/IFAS
So what is IPM and why should it be used?
IPM is a combination of methods used to manage pests that has the least harmful effect on non-target organisms and the environment. The four categories of IPM are:
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cultural practices
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biological control
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mechanical/physical
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chemical control
There is not one perfect IPM plan for all landscape situations, but there are some key components to help develop one for any situation.
- Prevent pest problems – choose the Right Plant for the Right Place! Proper planting technique, choosing resistant cultivars, and good maintenance all contribute to overall health and can influence how likely plants are to survive disease, insect, or weed invasions.
- Scout for pests/damage – understand what pests are likely to target common landscape plants. For example, St. Augustinegrass is susceptible to attack by chinch bugs; know what to look for to spot an infestation early.
- Accurately identify the pest – it’s okay to ask for help with this! Your county extension office is a great place to start for both identification and control recommendations. Many times treatments are applied for the wrong pest and that is a waste of your time and money and it can make it harder to get a correct diagnosis.
- Follow control action guidelines – have a plan in place for threshold tolerance. How many pests/amount of damage is okay before
Chinch bug nymph. Photo: Julie McConnell, UF/IFAS
action is taken? What action will you take? Use least toxic methods first and combine the four methods listed above. If using chemicals, know how they work (mode of action) and be sure to rotate properly to prevent resistance.
- Evaluate and revise – continued scouting for pests will indicate if the method is working. Keep records so that you can make changes that will increase effectiveness.
If you are interested in learning more about Integrated Pest Management, visit the IPM Florida website .
by Carrie Stevenson | Sep 30, 2014
Last week, the Okaloosa County Health Department issued a rabies alert after three bats were determined to have the illness. A “drive-through” rabies vaccine clinic was organized for pets, and warnings were issued throughout the region about making contact with wild animals. One radio broadcast played an interview in which a health department staffer urged people “not to attract wildlife to your yard.” While they were focusing on unsecured trash and pet food, I found this advice unsettling, for as an Extension Agent I’ve promoted the practice of attracting wildlife to yards for many years—birds, butterflies, and even (especially) bats. Raccoons, not bats, have the greatest incidence of rabies (based on data collected from 1992-2011), by a factor of almost seven times that of bats. In the scare of a rabies outbreak, it can be easy to overreact or overlook the many benefits that wildlife provide to our neighborhoods.
There are, of course, practical ways to go about living with wildlife without endangering your health or that of your family and pets (including making sure pets have the rabies vaccine).
Use Caution around Injured Wildlife
Most wildlife rescue organizations do not have the staff to pick up injured animals and ask those who find one to bring them in. However, sick or injured animals may respond aggressively as an intuitive protective measure. If you are taking an animal to a wildlife rehabilitator, be sure to approach it gently and use a blanket or large towel to pick up the animal, and place it gently in a box with a ventilated lid. Great information on responding to injured or deserted animals can be found at the Wildlife Sanctuary of Northwest Florida website. Keep in mind that bats are flying animals and spend almost no time on the ground. They do not chase people and are primarily concerned with catching insect prey. If you find a bat on the ground, it is most likely sick. County animal control or private wildlife responders can also help if you are concerned about interacting with a sick animal.
These twin Seminole bat pups were found on the ground with their mother and nursed back to health at the Wildlife Sanctuary of Northwest Florida. Photo credit: Carrie Stevenson
Use Care When Retrieving Dead Animals
When bird flu, West Nile or rabies hits an area, health departments sometimes ask that suspect animals be reported for testing to confirm the cause of death. Even if you are just disposing of the animal, be sure to use gloves and place the animal in a sealable plastic bag to prevent spreading germs, and wash your hands after handling it. If burying, place at least three feet deep and away from wells or water sources.
Enjoy Wildlife from a Distance
Disturbing healthy animals while they are feeding or resting can cause unnecessary stress and reduce their hunting success. Animals’ natural behaviors are fascinating to watch, so be sure and do so from a respectful distance to allow them to interact normally with their environment.
by Matthew Orwat | Aug 4, 2014
Holly leaf infected with Phyllosticta. Image Credit Matthew Orwat
Phyllosticta lesion on holly leaf. Image Credit Matthew Orwat
The high humidity experienced in the Florida Panhandle during July and August has provided perfect conditions for fungal disease development on the leaves of a variety of ornamental species. One particularly noticeable pathogen is Phyllosticta. Fungi of the Phyllosticta spp. often cause large brown lesions on ornamental shrubs and trees such as magnolia, holly, Indian hawthorn, maple, crape myrtle and others. This dark to light brown spots are bordered with maroon, black or yellow rings, dividing the living and dead tissue. Black fruiting bodies, about the size of a pinpoint, are often spread throughout the diseased areas of the leaf. Infected portions of the leaf often drop out, leaving ragged remnants on formerly attractive shrubs.
Although preventative fungicides have been shown to reduce disease incidence, infected plants cannot be cured by sprays. Several mechanical strategies should be put into practice to reduce disease re-occurrence.
- Sanitation: Removal of leaf litter – Dead, diseased leaves contain the fruiting bodies, which will produce new fungal spores if left in the garden
- Thinning of branches – areas with poor air circulation are more prone to Phyllosticta
- Drip irrigation – overhead irrigation enhances the spread of a variety of fungal diseases. If overhead irrigation must be used, it should be done between 5 – 10 a.m.
For additional information about this and other disease, please go to the UF/IFAS U-Scout disease ID site.
Early statge Phyllosticta. Image Credit Matthew Orwat
