Oleander caterpillars, which are active on some oleanders during summer, can provide a number of gardening lessons.
Oleander caterpillar moth on lantana flower. Photo credit: James Castner, UF
The adult moth is striking in appearance. The bluish to purplish moth has white dots on its black wings. The moths resemble wasps as they fly in and around oleander shrubs.
It’s the orange caterpillars with black spots and black hairs that cause problems for some gardeners.
Caterpillars are the larval stage of butterflies and moths. In order to enjoy watching butterflies and moths feeding on the nectar of flowers, some of the caterpillars must survive to become adult butterflies and moths. This is lesson number one.
Oleander caterpillars usually only feed on oleander plants. Oleanders are native to areas of Europe and Asia. This is lesson number two.
Oleander caterpillar, Photo credit: Paul Choate, UF
Oleander caterpillars benefit by us planting their food source in Florida.
This relationship between pest and plant is referred to as the key plant, key pest concept. Some other examples include St. Augustinegrass and chinch bugs, gardenias and whiteflies, crape myrtles and crape myrtle aphids, azaleas and azalea caterpillars, camellias and tea scale, roses and black spot, pecans and pecan scab, squash and squash vine borers.
Understanding this concept can be helpful in designing a “low maintenance” landscape.
When you plant roses, you plant everything that goes with roses, including the time and money required to maintain them. This applies to St. Augustinegrass, pecan trees, squash and oleanders. This is lesson number three.
Oleander caterpillars can temporarily damage the appearance of oleanders. But they cause no long-term damage for the plant. This is lesson number four. The damage is aesthetic. Oleander caterpillars can consume great numbers of leaves. However, if the plant is otherwise healthy, new leaves will be produced and the plant will continue to grow. The damage is temporary; there will be no evidence the plant ever had a problem.
To spray or not to spray for oleander caterpillars has to do with a person’s tolerance level.
If you can’t tolerate having oleander caterpillars around and the temporary aesthetic damage they cause, consider the use of Bacillus thuringiensis. It is sold under a number of brand names and many times is referred to as Bt. This bacterium only controls caterpillars so it is friendlier for the beneficial insects. When using any pesticide, always follow the label directions and precautions.
Here are links to UF/IFAS Extension publications with more info.
Austin N. Fife, PhD student, Entomology
University of Florida IFAS
North Florida Research and Extension Center
Phyllocoptes fructiphilus: a new threat for Florida roses
Figure 1: Phyllocoptes fructiphilus . Image Credit Austin N. Fife, UF / IFAS
Phyllocoptes fructiphilus Kefier is a microscopic plant-feeding arachnid belonging to a group of spindle-shaped mites known as Eriophyoid mites. Eriophyoid mites are second only to spider mites in their economic importance and potential for plant damage: some species create galls, others deform plants with their feeding activity, and a few species are capable of spreading viruses. Fortunately, eriophyoid mites very host specific and P. fructiphilus only feeds on plants in the genus Rosa, which includes all of the true roses which we are familiar with.
P. fructiphilus does not cause damage by its feeding alone, but is a pest due to its relationship as the vector of an emaravirus: Rose rosette virus (RRV). RRV infection creates Rose Rosette Disease (RRD), with the following symptoms: witches’ brooms/rosetting, deformed flowers, increased prickle density, elongated shoots, reddened leaves and stems, and increased die-back which ultimately kills the rose host. RRD is the most serious disease of roses, creating millions of dollars of losses for growers. Rose Rosette Disease and the mite have invaded the southeastern United States as the non-native Rosa multiflora (Thunb) has spread invasively towards the eastern coast and by the introduction of infected roses from out of state into Florida.
Figure 2: EDDMapS. 2020. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/
RRD was initially detected in Florida in 2014 on 15 plants; however, the plants were destroyed and P. fructiphilus were not detected on the roses after that time.
In early 2019, a survey of predatory mites on roses found eriphyoid mites in samples obtained while surveying roses in Leon County, Florida. The mites were sent to the Florida Department of Agriculture and Consumer Services – Department of Plant Industry (FDACS-DPI) and were all identified as P. fructiphilus by Dr. Sam Bolton. To date, none of these roses have shown signs or symptoms of RDD and none of these plants have tested positive for presence of the virus.
Figure 3: Black dots indicate individual sites which have been surveyed for Phyllocoptes fructiphilus. Orange dots indicate a number of sites with populations of P. fructiphilus detected in Leon county, Florida. No symptoms of Rose Rosette Disease have been seen on these plants to date. Image Credit Austin N. Fife, UF / IFAS
This is the first recorded instance of P. fructiphilus in Florida and is worrisome despite the absence of the virus. Fortunately, RRV is currently not established in Florida. However, the presence of P. fructiphilus, along with past detections of RRV in Florida warrants an increase in monitoring efforts for the mite and virus in Florida.
Figure 4: Typical symptoms of Rose Rosette Disease. Image Credit Austin N. Fife, UF / IFAS
How can I identify roses that have Rose Rosette Disease?
It is difficult to identify the symptoms of RRD in the field for a few reasons. Primarily, there are different growth habits for different rose cultivars. What appears to be ‘excessive thorniness’ in one cultivar may be normal for another, and is can be easy to mistake the redness of new flush with symptoms of the RRD. In addition, glyphosate damage from improper use of Roundup or similar products can have a very similar appearance to diseased roses. The best way to verify RRD infection is to use molecular testing for the virus. Identifying the presences of eriophyoid mites is useful for diagnosis, but they are too small to see with pocket loupes and are difficult to find unless there are large numbers of mites. To properly identify an eriophyoid mite as P. fructiphilus requires the use of a compound microscope with a specially prepared microscope slide of the mite, as well as reference materials and a trained individual who knows what characters to look for.
What to do if I suspect that my roses are infected with Rose Rosette Disease?
We recommend reporting suspected cases of RRD to your local extension agency or the Florida Department of Agriculture.
Where should I send my samples?
Plant Disease Diagnostic Clinic at the North Florida Research and Education Center in Quincy: https://nfrec.ifas.ufl.edu/plant-pathology-clinic/
Mathews Paret, Director, Plant Disease Diagnostic Clinic – UF NFREC (850) 875-7154, email@example.com
UF/IFAS Disease Diagnostic Center in Gainesville:
- 392-1795, firstname.lastname@example.org
2570 Hull Rd Gainesville, FL 32603
Florida Department of Agriculture and Consumer Services – Division of Plant Industry
1-888-397-1517 Helpline (352) 395-4600 (Helpline Number, Outside of the United States) DPIHelpline@FDACS.gov
The Doyle Conner Building 1911 SW 34th St. Gainesville, FL 32608
Figure 5: Phyllocoptes fructiphilus is a refuge-seeking mite ,which hides under rose sepals, which are covered in tiny glandular plant hairs known as trichomes that protect the mites. Image Credit: Austin N. Fife, UF / IFAS
How Can I Manage Rose Rosette Disease?
Currently, there are no commercially available rose cultivars known to resist Rose Rosette Disease or Phyllocoptes fructiphilus. A major difficulty lies in the cryptic nature of these mites, which hide underneath the rose sepals. It is important to consider this when considering which control methods to use. Methods which require direct contact with the mites to kill them are unlikely to work.
This makes it difficult for chemical applications which require contact with the pest to work.
Keeping that in mind, there are a few things you can do to reduce your risk of RRD and prevent the spread of the mite:
- Eliminate infected wild roses nearby
- Heavy pruning followed by horticultural oil spray may reduce populations of the mite, but cannot prevent a viral infection from spreading.
- Space plants so their leaves and roots don’t touch
- Dispose of diseased roses properly: bag up infected materials and dispose of in areas away from other roses
- After removing infected plants, spray remaining plants with miticides recommended at https://roserosette.org/control/
- Spray uninfected plants adjacent to removed (infected) plants
One of my favorite native plants is winged sumac. I like this plant not only for its ornamental beauty, but also for its fruit that can be dried and used as seasoning and to make tea. So you can understand my concern when one of my prized winged sumac plants had distorted leaves.
Eriophyid mite damage on winged sumac. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
After doing a little research and speaking with one of our UF/IFAS Specialists, I was able to determine that the leaf distortion was caused by eriophyid mites. Mites are not insects and are more closely related to spiders. They normally have four pairs of legs, however eriophyid mites only have two pairs of legs. They are microscopic, elongate, spindle-shaped, and translucent.
An eriophyid mite. Photo Credit: USDA, Agricultural Research Service.
Eriophyid mites cause galls (sometimes called witch’s broom) on various species of ornamental shrubs. Symptoms include early and late bud distortion, distorted leaves, and possibly plant death. In fact, the species Phyllocoptes fructiphilus is the vector for the viral disease of roses called Rose Rosette Disease. Sometimes the damage can be confused with herbicide damage.
Control options are currently being evaluated for eriophyid mites in the home landscape. Removing distorted plant material and removing it from the site can help prevent the spread of mites. If you suspect eriophyid mites are the cause of your distorted plants then samples should be collected. To collect samples: 1) Prune off symptomatic plant material and immediately place into a vial with rubbing alcohol; 2) label with collection date, plant species, and location; 3) mail to the Landscape Entomology Lab in Gainesville at P.O. Box 110620, Gainesville, FL 32611.
For more information on eriophyid mites and the sampling process, please see the fact sheet “Unusual Galls on Woody Ornamentals” from Erin Harlow and Dr. Adam Dale.
For more information on other mites that could be infesting your landscape, please go to this link from the Mid-Florida Research and Education Center in Apopka, FL.
Monsieur Tillier – Tea rose from the late 1800s. A good choice where a large, free-flowering shrub is needed – Image Credit Matthew Orwat
Home Gardeners, when they think of roses, their mind inevitably turns to the ‘Knockout’ rose and its offspring. That’s fine, there’s nothing wrong with ‘Knockout’ roses, it makes a great ornamental landscape plant, and it’s easy to propagate.
With all the ‘Knockout’ mania, since the early 2000s, many garden roses, that are well adapted to the Northwest Florida climate, have been left out of the home garden to a large degree.
Several roses, which were grown in Florida commonly in the last hundred years, and recommended by former University of Florida president H. H. Hume in his book “Gardening in the Lower South,” are still grown here today. To obtain these roses gardeners must look to small nurseries scattered throughout central Florida and Alabama, or order them from larger nurseries in Texas where the “Texas A&M Earthkind Rose Program” has taken off.
Below are a few examples of easy to grow roses, that are just as disease resistant as the ‘Knockout,’ but offer more variety in color and form that home gardeners might enjoy as much as or more than ‘Knockout’. They have been grown successfully throughout southern Texas for over 30 years, and at the Washington County Extension Office for the past seven years without spraying fungicides or insecticides. Several of these cultivars were also involved in a 3-year rose trial at the UF/IFAS North Florida Research and Education Center, in Quincy.
One caveat I have regarding these roses is that disease resistance is lessened when irrigated with overhead irrigation. Even the most disease resistant roses will develop issues if leaves are constantly left wet.
Belinda’s Dream makes a moderately sized shrub and produces large flowers, especially in the spring and fall. Image Credit – Matthew Orwat
‘Belinda’s Dream‘ was bred by Texas A&M Professor Robert Basye in 1988, as a culmination of years of intense breeding and selection for disease resistant landscape and cut flower roses. It makes a 4-5 foot shrub that grows about 3 feet wide. Apple-green foliage clothe its pleasing shrub form. It’s free flowering but not overly vigorous, so it’s easy to keep in bounds. Disease resistance is high, there’s rarely any blackspot of note, under no-spray conditions, and only slight powdery mildew in a few years when conditions are favorable for fungus development.
In cool spring or fall conditions, the clear pink flowers can top six inches in diameter, and contain over 200 petals, but regular hot conditions during the summer usually reduce flower size to four inches. This rose loves to be part of mass plantings, particularly when planted 3 feet apart in a triangular formation. It has a reputation as being moderately easy to propagate.
Rosette Delizy is very colorful and disease resistant. A great addition where a spot of color is needed – Image Credit Matthew Orwat
‘Rosette Delizy‘ is a French Tea rose that was introduced to the U.S. nursery trade in the mid-1920s. Since it was bred before the days of modern fungicides, it sports excellent resistance to disease. It shows no powdery mildew, and only the occasional leaf with blackspot under no-spray conditions.
This is strictly a rose for the coastal south, since it does not like cold temperatures, and cannot thrive north of zone 7b without protection.
Color is striking, opening yellow with petal edges changing to pink as the flowers age. Cooler weather brings out deeper russet and maroon tones. It has a light “tea” fragrance. This mannerly shrub gets 4-5 feet tall and 3-4 feet wide. It requires very light pruning, and can actually be killed from heavy-handed gardeners with shears in hand. Minor flaws noted in this rose are that it is somewhat sparsely foliated, and somewhat difficult to propagate.
Madame Antoine Mari – The perfect buttonhole rose produces flowers with delicate, soft colors perfect for arranging. This rose is a mannerly grower suitable for smaller landscapes. Image Credit Matthew Orwat
‘Madame Antoine Mari’
‘Madame Antione Mari’, a Tea rose, was introduced in 1900 when the buttonhole rose was all the rage. Massive quantities of perfectly formed delicate buds of pink and ivory quickly open into 3 inch flowers that decorate the bush like butterflies fluttering in the wind. Re-bloom is fast. Additional interest in the landscape is created by the deep red color of new foliage.
This makes a mannerly shrub for the small landscape, easily kept at 3-4 feet tall, and 5-6 feet wide by light pruning. Disease resistance is above average in a no-spray garden, with very low blackspot infection rates, and only occasional powdery mildew. This rose has been found to be easily propagated with the author reaching near 100% success rate.
Mrs. B. R. Cant at the Quincy rose trial in 2013.
‘Mrs. B. R. Cant’
No mention of easy to grow roses is complete without the mention of ‘Mrs. B. R. Cant’. In the trials UF/IFAS horticulturists performed at Quincy and Plant City, this variety was rated the best performer. It has been in continuous cultivation since 1901, and is often found at old home sites and gardens in Washington County.
This makes a large garden rose, easily topping 8 feet in height, and just as wide. Deep pink flowers are borne profusely from March to first frost. Disease resistance is outstanding, and it’s easy to propagate. Plants are densely clothed in medium green leaves. This rose is often grown in hedges as a substitute for a fence. One of the best all-around garden roses for the gulf south.
I provide presentations at workshops on these roses multiple times a year, throughout the Florida Panhandle. The recurring question I get is, “Where are these roses available locally?” Hopefully this article will inspire some local gardeners to try these easy to grow roses, and others, since these are just a few of the roses available that do very well in North Florida under no spray conditions. If you are interested in more information, contact, Matthew Orwat at UF/IFAS Extension Washington County.
On Saturday, September 16th, 2017, from 9AM to 12PM, UF / IFAS Extension Washington County will be providing a rose gardening workshop for gardeners across the Panhandle. Many roses are hard to grow in the Florida Panhandle without investing considerable time and energy into spraying for insect and disease problems. This workshop will teach attendees how to select and sustainably grow roses adapted to the hot-humid conditions of the Southern Gulf Coast. There will be opportunities for outdoor learning and hands-on activities.
- Selection of disease resistant rose cultivars adapted to the lower South
- Resources to obtain hard to find easy care rose cultivars
- Soil and Nutrient Management
- Disease and insect management
- Rose Propagation
Participants will be given the opportunity to propagate their own rose and take home their own propagation assembly to grow their own roses from scratch.
Refreshments will be provided and a door prize will be available.
Address: Washington County Ag Center Auditorium, 1424 Jackson Ave, Chipley FL 32428.
Pre Registration required for count: Contact Nikki or Cynthia at 850-638-6180 or email Matthew Orwat at email@example.com
or register online at eventbrite HERE !
When you don’t know what’s ailing your plant, ask an expert.
Many gardeners get stumped when a favorite plant of theirs comes down with a strange “something”. Many of these gardeners know about UF/IFAS Extension and call their local horticulture and agriculture agents for assistance in figuring out what’s going on. However, even these experts are often stumped by what they see. Fortunately, the agents have another layer of experts to fall back on. In addition to the resources in Gainesville, we have the Plant Disease Diagnostic Clinic, located at the North Florida Research Center in Quincy. Plant pathologists here can help determine what fungus, bacteria, virus, or viroid may be the problem.
Plant pathologists are basically plant doctors. They use all sorts of sophisticated techniques to determine what is the cause of a particular plant problem, from growing out fungal spores to examining DNA. Not only do these plant doctors tell us what the ailment is, they also provide recommended cures, or control options. They are also doing research to prevent different diseases from taking hold in our area and reduce the impact on our local growers.
Plant pathologist at work!
At a recent workshop in Quincy, we learned that plant pathology researchers are working on a fungus that affects watermelons, virus and bacteria that can wipe out a farmer’s tomato crop, and a virus that could impact our local roses. Working as a team of scientists, they study these pathogens in the lab and conduct controlled field experiments to figure out which techniques are most effective. Some of this research is leading to different methods and/or products that can help growers and gardeners alike keep their fields and landscapes healthy.
So, if your plants have problems, please contact your local Extension Office. If they don’t know the answer, then the network of scientists, including plant pathologists, in the UF/IFAS Extension family can be called on for backup to provide you with the best possible answer.