It could be a fungus called “sooty mold” that feeds on honeydew (a sticky sap sucking insect liquid poop) that covers the leaf surface.
Learn to identify sap sucking insects (aphids, whiteflies, treehoopers, mealybugs and soft scale). They suck the plant nutrients from the leaf with their hypodermic needle shaped mouthpart. The honeydew (insect waste product) is clear in color and if you watch the feeding insect you may see a honeydew droplet attached to the insect’s posterior. So grab your magnifying glass and hunt for the offending sap sucking insect. If the sooty mold is located on the top of the leaf surface then the sap sucking insect is on the bottom of the leaf or the plant above.
In order to remove the sooty mold one needs to control the sap sucking insects. The first step is to determine if you have beneficial insects (lady beetles, lacewing larvae, parasitic wasps) http://edis.ifas.ufl.edu/in120 are doing their part by eating the pest insects or laying their eggs in them. If the pest population is expanding then the next tactic is a strong stream of water to blast the pest insects off the leaves or pruning out the pest problem. If you do choose a chemical control start with the least toxic pesticides to minimize the loss of beneficial insects. The best least toxic pesticide choices are horticultural oils and insecticidal soaps.
Check out the University of Florida Extension weblinks below for more information about sooty mold and it’s control and beneficial insects:
These links were updated in April, 2013.
Photo Credits: UF/IFAS Kim Gabel
September 14, 2021
Thank you for sharing your blog, amazing detailed information, it helps us a lot. Thank you!
September 9, 2021
Great information; I don't think that many folks think about this and it's important. Thank you!
August 24, 2021
I don't know as we have the same problem. HELP!!
August 23, 2021
Hi Krista. I would recommend working with your county Extension Agent to determine the cause of decline in your plants. There are a variety of things that can cause witches broom, including herbicides. Ground Clear is not the only product that could cause these symptoms. I also sent you an email.
August 22, 2021
I have been searching all over for an explanation of why the landscaping plants that surround the entire perimeter of my property is being effected by witches broom in one form or another. I have been to the county extension and they said I, or a neighbor was using too much ground clear. Not the case from what we can see. We are not using anything on the yard because of our dogs. I've sprayed weedkiller in the cracks of the road so the city wouldn't do it in the heat of the day. Anything applied to yard has been sparingly and sparse. Mostly because of the animals. 2 years ago plants started to show up with the witches broom. Random plants, all different varieties including trees, some right next to healthy. Now it's still happening, but only to us. No one in neighborhood is having this happen. Have you ever heard of this? Please offer a suggestion.
August 19, 2021
Really wonderful information can be found on web blog.
August 12, 2021
Great article and very useful information.
July 24, 2021
June 27, 2021
Thanks for re-writing the arrival above. That was very helpful.
June 22, 2021
A fun and informative article. Thank you
June 21, 2021
Blue land crabs can be harvested November through the end of June. They can only be harvested by hand or with a landing or dip net. There are no chemicals registered for control of blue land crabs and it is illegal to use traps, bleach or any other chemical solutions. https://myfwc.com/fishing/saltwater/recreational/blue-land-crabs/. The only way to try to keep them from burrowing in your yard is to use some type of barrier (fence) to keep them out.
June 16, 2021
4 times I have had retina issues. Still not sure but I think it may have been caused from milkweed. one or both eyes were in pain and it looked as though I was looking through a frosted glass or heavy fog. Very scary. Dr. prescribed a steroid. It had improved results within 2 days. It was a mystery to the Dr. but as I think about it, it may have been the milkweed. Now I either wear gloves and always wash after touching the milkweed.
June 5, 2021
I live on a canal and my lawn is full of land crab holes. I am concerned that someone is going to be injured because some holes are quite large and not always easy to see. Hoe can I eradicate them humanely?
May 19, 2021
Thanks for sharing with us this digital hurricane kit. filehippo
May 15, 2021
I purchased seeds for Everglades cherry tomatoes 2 years ago. They have reseeded. I just water them. They are prolific and dependable. Mrs. Anderson Bradenton, Flo
May 12, 2021
Witches broom is caused by a variety of different causes from mites to diseases, but all look very similar. The abnormal growth caused by these herbicides looks like witches broom, yet it is more widespread throughout the entire plant. You would need to determine what is causing the abnormal growth in your hedge plants. You can contact our Master Gardeners and/or bring in a sample to our office for identification.
May 12, 2021
How to determine if you have witches broom in hedges
May 7, 2021
We have had them for YEARS, this is the first article I have ever seen written about them. We are on the West Coast. they are GREAT!
April 8, 2021
Hey Alicia. It was a very good article. Thanks for writing. from kimia piarom
March 24, 2021
Great explanation about holiday planning. Thank you for sharing an amazing article.
March 17, 2021
It is so important to hire a professional tree service that can actually ensure that properties have hurricane preparedness. Consulting an arborist to figure out what to do in order to be prepared for hurricanes is a great step to make sure there are not any additional damages caused by trees or other debris that could have been trimmed or removed from the property.
March 12, 2021
Hi Michelle, I attended Dr. Chouvenc's presentation and have been kicking myself for not taking better notes. Now I have your excellent summary. Thank you!
March 8, 2021
Great job; well conveyed information that is very important, especially for those in the Tree Industry to recognize and treat. Thank you.
December 27, 2020
Great article, Michelle! My soil is hydrophobic so I am composting directly into my gardens. When the hedge is clipped I have the men place the greens in my large compost bin.I only discard branches. I have been composting since I married in 1967!!! I'm in favor of recycling all and everything. Again, thank you! Pat Nolan
October 28, 2020
Nice article! I just made some holy basil and roselle, and it's delicious! I found Roselle for sale at Bravo for $2.00 for a big bag of it in the produce section. It mixes nicely with other herbs. Best Wishes!
October 5, 2020
They are present year-round in south Florida and the Keys. The eggs can be found in clusters on the underside of the leaves. This fact sheet provides more information. https://trec.ifas.ufl.edu/mannion/pdfs/OleanderCaterpillar.pdf
September 22, 2020
when do you know if the eggs are being laid...what time of year? is there some indicator..?
September 21, 2020
Thank you for this very informative and helpful article. I agree that getting started early in the morning can help set the tone for a good, productive day. In the office, I was always most productive during the early morning hours while the atmosphere was still quiet. This also allowed me to complete any unfinished work from the previous day, as well as adjust my existing agenda for the day ahead if needed. Taking short breaks and ending the day while working from home has been challenging for me at times, even though I have worked from home before. This article is a great refresher for me. Thank you!
July 18, 2020
This article was most helpful- we are currently selling a beautiful mountain retreat and purchasing a home in Islamorada, Florida-I will miss my bird life here and am hoping to attract and enjoy the native species of the keys
July 8, 2020
Hi Susie, milkweed is not a host for oleander caterpillars. However, your mandevilla is a host, along with desert rose and rubber vine.
June 7, 2020
I found an oleander caterpillar on my milkweed. I have no oleanders. What else can they feed on?I have a mandevilla and pentas nearby...
April 21, 2020
This is a great publication about seed sources for Florida homegrown vegetables https://edis.ifas.ufl.edu/ep486. Keep in mind, seeds have been in high demand and some companies are no longer taking new orders, keep trying. Additionally, Key West Botanical Garden grows them and when they are open to the public again, should have plants available.
April 21, 2020
Where can we buy Everglades tomato plants?
April 19, 2020
I agree but have a love/hate relationship with my VPN it makes it very slow to get anything done! Sure I can get to my files but is slows me to 25% efficiency! I have been using our approved one drive to keep my working files in and Office 365. Let me know what works for you and maybe I can include it in the article. Thanks
April 19, 2020
What about using VPN? My manager insisted on me getting Atlas VPN once I started working from home and apparently there have been news articles that there will be more hackers invading private home networks to steal all kinds of company data
April 17, 2020
Great info! Thank you!!
April 15, 2020
April 15, 2020
Thank you ladies for a great article. These tips are so helpful. Working from home is a challenge and can make it hard to stay focused. I don't know about the dress nicely suggestion (I mean, actually changing out of my peejays should be enough), but scheduling time to check email instead of keeping it open is something I started at the office and carried over at home. It definitely helps limit some of the distractions the little envelope provides when it pops up.
March 28, 2020
What an interesting post, I just read it from start to end your blog post, An informative blog. These plants grow from creeping, underground rhizomes and can also reproduce by seed. Thanks for sharing such a great post ever.
February 6, 2020
Hi David, thank you for your comment. The link has been updated.
February 6, 2020
If you live in Monroe County, you can contact our office for plant identification. Our contact information is listed on the homepage of our website, or go to the environmental horticulture page to reach the agent directly. For quickest results, you can email pictures of the plants you need identified. If you live outside of Monroe County, you can contact your local Extension office for help with plant identification.
February 4, 2020
I need to have invasive plants identified
January 2, 2020
The link to the Whitefly article on this page is no longer valid. Since we are now seeing activity at the Golf Club in Key West we would appreciate an update to that link as people are again asking for a way to control them. Please contact me and I will put it on our website.
August 23, 2019
Hi Judy, I wish you had contacted the Extension Service. Those are not Oleander Caterpillars you killed, they are Gulf Fritillary butterfly caterpillars. Passion vines are actually a larval food source for three different species of butterflies, including our State butterfly, the Zebra Longwing. This fact sheet has more information. http://entnemdept.ufl.edu/creatures/bfly/gulf_fritillary.htm
August 23, 2019
I’m growing Passion Flowers. They’re so beautiful and attract and . I even have beautiful Monarch Butterflies now! Passion flower is a climbing vine and spreads everywhere. But that’s ok with me. Last year, my foliage on the vines started disappearing! I noticed this ugly worm, or orange caterpillar with black spikes all over. He was devouring the leaves so fast I couldn’t believe it! An entire vine was eaten overnight I didn’t know what they were, and I didn’t kill them because I thought they might be Monarch larvae. It’s funny...they didn’t eat any didn’t eat any other plants...just the Passion Flower. It looked awful with only vines with no leaves. So I went out there yesterday with my scissors and searched for the little suckers. I found about 50 or more and I just cut off their heads with scissors. What a hassle! And I felt so guilty for doing that...I really did. From now on, I’ll make up the mixture of stuff you guys are using to get rid of these little destroyers. Thanks!
July 13, 2019
Do they bite and are they anything to worry anout if they do ?
July 2, 2019
I guess I can agree with letting them be, but maybe it depends on the type of scorpion. This article about Arizona scorpions advocates getting rid of them.
December 13, 2018
My Fiddlewood is suffering sever damage from these pests. At first I thought it was the cold snap we were experiencing. I live in eastern Martin County.
November 14, 2018
This was a best understandable address about the hazards of trees but you make sure gutters are cleaned out so water can flow freely and not contribute to roof damage or leaks.Landscape Hurricane Preparedness should be included in your hurricane plan. Don’t wait until the last minute to prepare your landscape. It can be dangerous and debris may not get picked up in time and become another hazard. Remember, just because a tree is damaged in a storm, doesn’t mean removal is the only option. Contact a consulting arborist to do a risk assessment and determine if your tree can be saved. For more information on assessing damage and restoring trees must concern this kind of matter with the tree care company services . Thanks.
November 13, 2018
Hi Bruce, Thank you for your suggestion. There have been reports of that product killing the tree cambium, resulting in the death of the tree, when used for Gypsy Moth. Which is why it wasn't mentioned in the article.
November 11, 2018
You may wish to consider Tanglefoot Tree Insect Barrier from Amazon or wherever found. Inexpensive, easy to apply, environmentally safe and long lasting.
September 12, 2018
Hi Robert, It does not sound like the same caterpillar. You can contact the Extension Service in your County for accurate identification. A photograph or physical sample might be required. Palm Beach County Extension Service (561) 233-1700.
September 12, 2018
I live in SE Florida, Delray Beach. My Royal P has some small caterpillars hanging down from the canopy on long threads every morning. Not a lot, but a few. They are 1/4" by 1/16" and light yellow/green in color. Do you know what they are? I will start watching to see if I have any of those described here climbing the trunk in the early evening.
August 22, 2018
Hi Pat, Thank you for your comment. We are big proponents of integrated pest management (IPM), and one of the principles of IPM is starting with more environmentally friendly options when the decision is made to control a pest. However, in this scenario, this is the best and quickest way to control this pest. Diatomaceous earth is made from the fossilized remains of tiny, aquatic organisms called diatoms and with its abrasive sharp edges, causes insects to dry out and die by absorbing the oils and fats from the cuticle of the insect's exoskeleton. Unfortunately, it will also absorb water and moisture from the air, rendering it ineffective from a pest management perspective in the landscape with our high humidity. Additionally, Bacillus thurengiensis (Bt) is a stomach toxin that would need to be ingested by the caterpillar to be effective. Another option you could try is Spinosad, which is a natural substance made by a soil bacterium, you may have to reapply a several times for complete control. Also, there has been some negative consequences with the use of the horticultural glue in trying to control gypsy moth in a similar way. The sticky substance ended up killing the tree cambium, resulting in tree death. Please keep me posted on the method of control you use and its effectiveness.
August 21, 2018
After seeing an article in the paper about the Royal Poinciana caterpillar infestation, I inspected my tree and had an army of them crawling up them about 8:00 PM. I purchased SEVIN brand dust and copiously applied it to the trunk in the late afternoon. No more caterpillars.
August 21, 2018
Knocking the caterpillars off into a soap and water solution is very effective. You can also use a product with the active ingredient Bacillus thuringiensis (Bt) which is a microbial insecticide and only harmful to caterpillars.
August 16, 2018
A lot of links are quoting the same information. Here is a link to a more helpful solution https://brisbanetrees.com.au/poincianas-and-caterpillars/
August 11, 2018
I tried straight vinegar and hadnt worked right away so I remembered I had some Trader Joe's Body Wash with Tree Tea Oil and Peppermint in it so I took that outside to the plant and within less than a minute after I poured some on the caterpillars, they fell off. Was actually shocked, but glad.
July 24, 2018
Good morning, If you are located in Miami-Dade, you can contact their Extension Service for help with any landscape issues. Their phone number is (305) 248-3311. Otherwise, if you are in Monroe County you could send me an email with pictures to firstname.lastname@example.org. Thank you for contacting us.
July 4, 2018
Good Morning Hoping you can assist. I planted a number of gumbo limbo trees in Nov ‘17 in Miami. They were doing really until the leaves on two of them recently started to curl up into themselves in hard, tightly wound shapes. Obviously something attacking them. Wish I could post a picture.
June 4, 2018
Hi Mr. Oswald, thank you for your comment. The post has been corrected.
May 31, 2018
Hi kgabel, You may wish to consider updating your statements above. Some, but not all, green lacewings (Chrysopidae) are "trash carriers", but no brown lacewings (Hemerobiidae) have ever been shown definitively to carry trash. Earlier reports in the literature to this effect all appear to be misidentifications of green lacewing larvae. Your left photo above is a chrysopid; the right photo is a hemerobiid. Cheers, John Oswald Prof. Entomology, Texas A&M University P.S. I'm a Neuroptera systematist...
May 21, 2018
You can go to the University of Florida's EDIS (electronic data information source) website and there are many publications about palm trees. You can also contact our office with any specific questions you may have. http://edis.ifas.ufl.edu/topic_palms Thank you for your comment.
May 21, 2018
Hi Roberto, Azaleas don't really grow down here. They are hardy to about zone 9b, we are zone 11. As for Royal Poinciana, I don't have personal experience, but I don't think its too much of an issue considering the size of the tree. Thank you for your comment.
May 21, 2018
Hi Paul, Thank you for the question. I am the new horticulture agent since Kim Gabel retired. Imidacloprid, which is a neonicotinoid, is not effective against lepidopterans (caterpillars). You could try Spinosad or a microbial insecticide with the active ingredient Bacillus thuringiensis, the strain specific to caterpillars. These will need to be sprayed early, at the first sight of an infestation. Bt is only effective against caterpillars and will not harm beneficial insects. Always follow label directions when using any pesticides. Please contact our office if you have any additional questions.
May 5, 2018
Will injecting Mahogany Trees with Imidacloprid prevent the the annual infestation of webworms? If it is applied as an injection, is it harmful to bees and/or are there other environmental issues? I know webworm presence on the Mahogany trees will pass with little harm to the trees, but they do create a mess and my neighbor gets quite upset.
February 12, 2018
I love reading an article that can make men and women think. Also, thank you for allowing for me to comment!
February 4, 2018
University of Florida, Institute of Food and Agricultural Sciences Extension outreach is a partnership between state, federal, and county governments to provide scientific knowledge and expertise to the public.
January 22, 2018
I have a business in the Florida Keys and would love to plant a poinciana tree and azaleas in my backyard. Does iguanas like those trees? If yes! what do you suggest for me to do?
December 5, 2017
This post is priceless. Where cɑn I find out morе?
October 16, 2017
I heard in the Cayman Islands according to the Sun Sentinel that they captured over 166,000 green iguanas in 2014 and the population grew to over 400,000 in 2 years. It was crazy explosive growth. We have to do a better job managing the green iguana population. - Kris Reynolds - Nuisance Wildlife Rangers
September 23, 2017
Good blog, I’m going to spend more time learning about this subject
May 11, 2017
Excellent article. I will be experiencing many of these issues as well..
August 4, 2014
The other months of the year may work, but again the recommended months are June-August. Variable weather conditions due to temperature and rain fall may make the soil hot enough or not. Regarding mint -
July 31, 2014
Re soil solarization - great idea. If we stay during summer I'll use it. In fact, I don't know why it wouldn't work Oct.-NOv., and March - May. Direct sun can get pretty hot then. If we can grow mint in Florida Keys, I'm doing so because here in Maine my mint bed all went to flowers and many bees appeared out of nowhere to work the site.
October 2, 2013
I'm having to deal with an infestation of birch leafminer. It's really awful seeing my trees cut up like that.
August 31, 2013
I think this caterpillar fell on my toe and although it didn't hurt days later I have this rash my toe
August 17, 2013
The bugs turn into ugly moth-like creatures. Just spray thyme or tea tree essential oil diluted in some water. I srayed this morning, and as the sun comes out, the caterpillars are dropping off the plant and dying.
May 1, 2013
Is the 2013 hurricane season supposed to be worse than normal? I've heard that climate experts are predicting more hurricanes in the Gulf this year, but I don't know how credible the sources are. If it's true, we better begin preparations asap!
February 7, 2013
Interesting how the pH level can vary so much, depending on location. I doubt that most people realize how many factors affect their gardening and landscaping!
February 3, 2013
Are more people (or landscapers) using organic fertilizers these days, or still chemical based? Specifically in the FL Keys?
August 9, 2012
As the name suggests, this is a bug with transparent wings. The rest of the body is dark, giving the bug a contrasting black and white appearance.
July 27, 2012
thanks a lot for the photos.
June 21, 2012
I attend college in South Florida. My roomie was surprised to find Uncle Sam and his brothers on her Yellow Mandevillas. So we transported them to our school property's plant. We also kept Uncle Sammy. I am appalled that y'all want to kill Uncle Sam and his brothers by freezing them to death. I think we should just transport them to someone else's plants. That way they can still live a hearty life. Shalom.
May 29, 2012
I have two caterpillars - yellow with silver dots feeding on two of my Desert Rose plants. I've raised butterflies, but never saw these caterpillars before. I am collecting Desert Rose plants - had no idea they would be eaten. Can I move these to another plant. It's midnight, just went out and picked 3 off my roses with leaves. What now?
May 10, 2012
As the name suggests, this is a bug with transparent wings. The rest of the body is dark, giving the bug a contrasting black and white appearance. what is career transition
May 2, 2012
Who is the person who said that caterpillars are never "beneficial"? They ALL turn into moths or butterflies which are beneficial -- so lets kill all the caterpillars and therefore there will be no more moths and butterflies on the earth! Geezz...
December 18, 2011
About 50 of those ate my desert rose over night and started eating a corn palm too. i tried killing them with a natural pesticide I had then got nervous because they were so many so I got out he big guns and downed them. They literally ate the leaves and flowers off the whole plant over night. scared me so bad i thought they would eat the whole yard by morning
December 1, 2011
Caterpillars are never considered "beneficial", as all caterpillars feed on leaves and cause foliar damage. They are considered pests if the damage is intensive and causes harm to the plant or if the damage is unsightly. I personally don't care as long as my plants don't die.
November 27, 2011
I found the caterpillars on my Desert Rose plant and sprayed them with a mixture of minced garlic and red pepper mixed with water. They dropped right off. I was concerned that I had killed a beneficial caterpillar.
August 20, 2011
thanks a lot for the photos. they are really beautiful. there are путевки в Черногорию cool photos too. Best wishes. keep it on)
September 10, 2010
Saw a green or blue crab, bigger than two adult hands wide, in Miramar, Fl. Do they hangout in canals and lakes too. Too dark for pictures. I thought it was a beach crab, had never heard of land crabs.
June 12, 2010
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June 9, 2010
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December 22, 2009
The product in the link will easily control the insects and release the sooty mold that they cause. It is also natural which is a must to keep florida beautiful. It was also developed in florida.
October 20, 2009
In Key West can you join forces with the mosquito control and add something to their spray which will help all of Key West save our hibiscus and other infected plants?
October 8, 2009
This comment has been removed by a blog administrator.
September 10, 2009
Regarding the Hibiscus Mealybug...I just recently moved back to SW Fl from out of state and purchased an older home with mature landscaping. There are several hibiscus and one was under severe attack from mealy bugs. I'm an organic gardener, so I wasnt interested in pesticides. I checked out the horticultural oils, but decided to try EMs (effective microorganisms). I didnt know if it would work, but I'm happy to report that one month later, I have lots of new growth and beautiful blooms. The mealybugs and the resulting damage (sooty, stumped branches,etc) are gone. I was pleasantly surprised, and continue to be amazed with EMs. I have no affiliation with the non profit company that makes EMs--EM America, but stumbled upon the product a couple years ago. It hasnt let me down yet. give it a try.
March 15, 2009
This blog has loads of useless info, thanks! Hope you will keep it up!
January 7, 2009
Nice web site!
December 9, 2008
I've heard the BEST way to get rid of them is to get a dog.
August 27, 2008
thank you, i think this is exactly what's on my tree - i was cleaning it off the other day wondering if i should try a fungicide or something. i'll look into the bugs!
August 18, 2008
There used to be a large land crab population at the corner of VonPhister and Whalton. Unfortunately, the city has installed injection wells at the same corner and we no longer have crabs there. Is the city/public works subject to the rules listed in this blog?
July 19, 2008
This comment has been removed by a blog administrator.
Comments are closed.