By: Bonnie L. Grant, Certified Urban Agriculturist
Sago palms are actually not palm trees but an ancient plant form called a Cycad. These plants have been around since the time of the dinosaurs and are hardy, tenacious specimens, but even the mighty may be laid low by tiny little pests. In this case, if a sago palm has white dots, you need to be ready for battle. White spots on sago palms are likely an introduced form of scale insect, which has become almost an epidemic in warm regions of the country where sagos naturally grow. To prevent the death of the cycad, you need to know how to get rid of white scale on sagos.
Cycad aulacaspis is only tempted by plants in the cycad family. Once you see it, you have an infestation that is very difficult to get rid of since it is likely on neighboring sagos and can be blown onto plants with each gust of wind.
The appearance of white fuzzy stems, leaves and trunks signals a huge problem. Scale is a tiny sucking insect and, in high populations, the bugs can sap the plant of much of its life-giving fluid and kill it.
The insects have a protective waxy armor, which is white to yellow. They are so tiny that finding the problem before the plant is overrun is almost impossible. Once the population has bloomed, all parts of your plant can be infected and the pest’s presence is obvious.
Treating sago palm scale is crucial to rescuing the plant’s health, but it’s not an easy process. This is because the insects can just blow back onto revived plants and their ability to hide in cracks, and even the roots, prevents some controls from working completely.
First prune off any infested fronds. Then apply paraffin based horticultural oil to all parts of the plant. Mix 3 tablespoons (44 mL.) of oil with water and spray the entire palm. Don’t forget under the leaves and the trunk. Apply two to three times with five days between each application. Neem oil can also be used.
For better control, use a systemic insecticide. These work best as soil drenches applied at the rate recommended by the manufacturer. The benefit of these is that the roots take up the chemical and the insects suck it out and die. It also can get the persistent scale on roots.
There is a beetle and wasp that are being studied for treating sago palm scale. As natural predators, they would be effective in reducing populations in a non-toxic manner. Unfortunately, they are not commercially available.
Persistence is usually the rule when treating sago palm scale. Don’t forget to spray consistently or the pests will make a grand return.
When a sago palm has white dots, it might just be a natural occurrence. It might be mistaken for scale insects but is not. This is instead called scurf on sago palms. It is a normal condition, and the scurf will eventually fall off as the leaf matures.
The appearance is white and forms in raised elongated bumps that line up along the rachis and the leaflets. There doesn’t seem to be any purpose to scurf on sago palms, but it doesn’t damage the plant and does not require treatment.
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I have a problem with white mold on my sagos. Can you tell me what to do about it?
Two types of scales attack sagos, and one of them, the Asian cycad scale, is the most damaging of the 20 or so scale insects in Florida.
The small individual insects suck sap from the fronds. They build to very large numbers and by cumulative effect weaken the plant enough to sometimes kill it.
Controlling them takes persistence and thoroughness.
You can spray with a horticultural oil (be careful to check the temperature restrictions) or Organicide, a chemical that is 95 percent fish oil. The oils are effective because they are able to coat the exterior of the scale insects and suffocate them. You must spray the tops and bottoms of the fronds and the trunk thoroughly to kill them. Recommendations are that you spray once a week for three weeks, then hose the plant off the fourth week.
There will probably still be some stragglers who reinfest the plant. But you may get 6 months of protection before they begin to build up numbers again. As soon as that begins, start the spraying cycle again. You can also call a commercial pest control company. They have a systemic product called Safari that is very effective. This type of scale insect can also feed on roots underground and this is the main reason these scales resurface on the leaves.
Sagos used to be considered a trouble-free plant. But there is hope - predatory insects have been released in Florida and are building up populations and spreading.
I am recycling orchids. I have found several plants that have already bloomed and were being tossed out and I'm going to try to keep them and bring them back into bloom.
This is a wonderful idea because orchids are really pretty easy to grow and keep happy. After some discussion, we determined that you definitely have phalaenopsis orchids and probably have a type of dendrobium. These are the most commonly found kinds of orchids and their needs can be met indoors, especially in the winter.
Phalaenopsis need more water than some other kinds of orchids. You'll want to keep them evenly moist - they do not like to dry out. They do best with bright light or indirect sunlight. East and north windows are good spots for them, although set back from a window on the south or west side is OK. Phals prefer temperatures in the 60s at night and 80s during the day. They don't rest like other orchids and live on a bloom-and-grow, bloom-and-grow cycle. They are getting the right amount of sun if they are olive-colored. Too dark green means too little sun, while red edges mean too much sunlight.
Your dendrobium orchid can get a little drier than the phal. It likes to get more sunlight than the phalaenopsis and can tolerate direct sun early or late in the day. One critical difference between phals and dendrobiums is that dendrobiums have a resting cycle. They go through a period of growth (look for roots and stem/leaf growth) then rest, then flower. When they are resting, they need less sun, a lot less water, and no fertilizer. Once they begin to look like they are perking up, move them closer to the windows again and start fertilizing. Dendrobiums like to be in smaller pots, so don't rush to repot, and when you must, choose a small pot.
During periods of growth, many orchid growers follow a "fertilize weekly, weakly" policy. Neither orchid is very tolerant of the days when our thermometers top 95 degrees, so you may want to plan ahead to bring them indoors then.
I have a gloriosa lily that has produced seed. How do I grow them?
Gloriosa superba (sometimes the names do fit) is a beautiful bulbing plant from South Africa. The 4-5-inch flowers are striking with red and yellow recurved petals. The flowers grow on a vining plant that can stretch up to 6 feet tall. All parts of this plant are poisonous, so it should be planted where children and pets won't be able to get into trouble with it.
To germinate the seeds, they have to fully mature. When they are mature, the pods will split and the red seeds (which look a bit like tiny tomatoes) will be revealed. They can be sown in a well-drained sterile seed soil mix. If you have any doubts about how well your seed mix drains, you can always add some perlite or vermiculite to the mix to aerate it further. It should take a few weeks for seeds to germinate.
The seeds will take 2-3 years to reach blooming size. Faster, more reliable results can be gained by planting a tuber. Bulbs can be divided for propagation.
Because these bulbs are from South Africa, they are acclimated to a very dry rest season and a hot, wet growing season.
Becky Wern is a master gardener with the Duval County Extension Service and the University of Florida/IFAS.
Asian scales (Aulacaspis yasumatsui), also known as Asian cycad scale or cycad scale, originated in Thailand. They attack sago palms (Cycas revoluta), which grow in U.S. Department of Agriculture plant hardiness zones 8 through 11. These pests cluster on a sago palm's roots, trunk and the undersides of fronds, feeding on the sap from the plant tissue. Asian scales appear as 1/8- to 1/4-inch, round to ovate, white to brown specks. Spraying Asian scale with diluted neem oil immediately after their discovery will stop their reproduction and eradicate them, saving the sago palm from severe damage or even death.
Put on a long-sleeved shirt, long pants and a hat to protect your skin from exposure to the oil spray. Wear eye protection and gloves.
Remove the lid from a tank sprayer and set it aside. Pour 1 gallon of water into the tank. Add 2 tablespoons neem oil to the water in the tank. Stir the materials thoroughly with a stick until thoroughly combined.
Screw the lid onto the tank tightly. Pull the pressurizing mechanism up and down until it becomes difficult to do so to pressurize the tank.
Lift the infested frond by its tip to expose the scale feeding on the underside of the frond's stem. Hold the sprayer's nozzle 4 to 6 inches away from the scale while spraying the liquid. Move the sprayer evenly and slowly back and forth over the insects to coat their surfaces completely. Shake the tank back and forth repeatedly every five to seven minutes to prevent the oil and water mixture from separating. Stop spraying once the neem oil solution begins to drip from the frond. Repeat this process to coat scales present on additional fronds.
Change into clean clothes immediately after spraying is finished. Wash the clothes worn during the application to remove any traces of neem oil. Wash your hands and face with warm soapy water to remove any traces of neem oil that may have accidentally gotten on your skin.
Make two to three additional applications of neem oil, spacing each application five to 10 days apart. Mix a new batch of solution before each application.
Store the bottle of neem oil in a dark, dry room with a temperature above 40 degrees Fahrenheit and below 80 degree Fahrenheit. Position the bottle in a spot away from children, pets and food.
Although they're tropicals that can take full sun, sago palms grown outdoors need part shade to prevent their leaves from burning. They also need soil that drains easily, yet not too fast. Moderately sandy soil mixed with good compost will retain some moisture, but won't stay overly soggy and cause the roots to rot.
Sago palms grow best in temperatures that range from 65 to 75 degrees Fahrenheit. Once the fronds become about a foot long, they begin to arch over.
Outdoor sago palms should be watered when the soil begins to dry out, or about once a week if there's not at least an inch of rainfall. Once they're established, the plants can tolerate drought and don't need regular waterings.
Fertilize outdoor sago palms every spring with a balanced, slow-release fertilizer, such as a 10-10-10. Follow the package directions for how much to apply. Like plants grown indoors, outdoor sago palms are seldom bothered by pests or diseases other than fungal root rot, which results from overwatering.
Hello - I posted this to the Identification group and got a reply that it is indeed scale of some sort -
Does anyone have a suggestion for treating / curing this? I am thinking of looking into trying 1 part fish oil to 100 parts water tomorrow, but it is going to be an education to figure out how to apply, etc.
I have found a quantity of tiny white specs on the UPPER side of a few fronds of several of my sago palms. there is nothing on the underside and it is not spead to all fronds of a particular cycad. I have attached a photo of the worst section.
I am in Louisiana and have read quite a bit of stuff on cycad scale problems in Florida, but the photos they show always look worse and they seem to consistently indicate more of an underside attack of the frond - especially in light infestations.
Could anyone please help with an identification and what the appropriate action would be to protect the plants?
David, If I was going to use the fish oil and water, I would atomize the spray. Here in Florida we do have some maladies when it comes to cycads, like lethal yellowing. They are usually very hardy plants that go back a long way in history. Imagine a dinosaur trying to devour one.
not too appetizing. I'd like to know if your methodolgy works on the white scale. Keep me posted and good luck.
Hopefully by "atomize" are you talking about using one of those pump-up-the-pressure spray bottles. I have one of those and intended to mix everything in that and spray. the only thing is - I saw something sold by the gallon called "Fish Oil Spreader Sticker" and I have no idea what that means (the company you could order it from didn't have a description). so I am just trying to figure out if there is anything aside from water and fish oil that I need in the mixture.
I am going to do some more digging around about it (no gardening pun intended), but if you have any further insight into how this is best done, please let me know.
Fish Oil Spreader Sticker emulsifies the oil/water mixture so you don't have to keep shaking it up to keep it adequately mixed. It probably also contains something to help the solution adhere to the foliage to better smother the scale.
So this is something that you add to fish oil, or does it already have the fish oil in it?
Depends on the product- check out the ingredients on the bottle.
RU "organic" only or willing to try another option?
I would certainly be open to investigating an option.
I thought I had removed enough fronds to escape the problem, but I noticed this morning that other fronds are turning brown near the core of the plant. so, please suggest away!
I've had the same problem. And it does seem to reoccur - drat! Imidacloprid is a systemic insecticide, and lasts for about 3 months. Best if watered in at the base of the plant, or injected into the soil, it is sold as Merit, and Bayers Advanced also has an imidacloprid product. There are more names listed in these links, which are very informative:
Because it takes some time for Imidacloprid to be taken up and effective, I would also use the fish oil or horticultural oil as recommended. You'll note that one of the articles adds Malation to the oil, and this combo can also be purchased pre-made.
I don't like using pesticides, but this stuff kills sagos and they are a very important part of my landscape. Whatever you decide to do, please let me know what you did and if it helped.
I used NEEM concentrate last summer on an every 7 day spray regimen. That's Asian leaf scale on your Sago. Problem is, they can burrow down into the soil. I got them on the run last summer, but as soon as I stopped the spraying, they came back, but not as bad. also, they seem to die out in the cold of winter, so I would start to spray with the NEEM as soon as your frost is over, and spray regularly throughout the summer. They multiply in the heat and humidity, too. Remove your most damaged fronds and put them into your TRASH can. Leaf scale is AIRBORNE. So, if one of your neighbors has it, it can migrate right back to your Sagos.
Best I can advise is diligence with the NEEM spraying, clean your tools with bleach between your plants. Isolate and/or quarantine diseased plants to a "HOSPITAL" area of your yard for individual treatment and attention. Do NOT use soils from diseased plants ANYWHERE else on your property check with your neighbors to see who else might have this and pass on the treatment regime to them.
Here're some links I used last summer. I've done much homework on Sago Palms, as I grow them for fun!
use a insecticide with maliathon spray it on ( Asian leaf scale ) is what it is and it will turn it all brown and die
i also used a power washer to clean off the scale
had 4 sago 's with the white flakes and all are ok now
Which product did you use with Malathion in it? I'm about to begin repotting and spraying my Sagos. Not nearly as much scale as last year, but a tiny bit. I'd like to get it on the run before the summer heat and humidy sets in.
Have you ever tried the NEEM Concentrate? It works well, and puts a tremendous shine on the Sago leaves. That's why I like it so much.
no i have never used neem
last year was the first time i heard of the white scale killing sago palm in this area. the local paper said to spray with malathion also to wash off the scale.
i used (ORTHO MALAITHION PLUS) insect spray from home depot, then washed it with a power washer later, on sale at target ,$80.00.
worked for me, good luck
Thanks, badwolf2. Yeah, I remember now. Ortho Malathion. I'll remember the power washer this summer!
Sago Palm-Killing Insect Sighted in Bexar County --------------- OCT. 2006
By William Pack, San Antonio Express-News
Oct. 17--The insect that is killing sago palms in the Rio Grande Valley has expanded into the San Antonio area and possibly other parts of South Texas, a researcher who is monitoring the outbreak said Monday.
"I wouldn't be surprised if it were everywhere in South Texas where we have sago palms," said Carlos Bogrn, a Texas A&M University extension entomologist, about the spread of the cycad aulacaspis scale.
The minuscule insect is blamed for destroying about half the sago palm population in Florida after it arrived there in the mid-1990s, probably from Thailand. Since then, it has infested palms throughout the Gulf Coast, reaching Texas in 2002.
The Corpus Christi and Katy areas were among the earliest to report the pest, but bigger tolls have been recorded recently in Cameron and Hidalgo counties, particularly in a line from Harlingen to South Padre Island. Plant specialists were not aware that the insect had moved north into Bexar until about 10 days ago, when worried homeowners began calling about white coatings on palms that indicated the scales had arrived.
Molly Keck, an extension entomologist in Bexar County, said other scales are creating problems for sago palms, but two of three samples from San Antonio palm owners confirmed that the aulacaspis scale, also called the Asian scale, has arrived.
"We've been getting tons of calls," Keck said.
Sago palms are a valued component of the state's $1.4 billion horticulture industry.
The scales reproduce rapidly and have not been restrained by wasps or other natural enemies, so they can grow from being barely noticeable to covering the fronds of the tropical plants in weeks. One expert estimates that the pest may have taken close to a $1 million bite out of the palm industry in the Valley already.
But there are effective treatments that palm owners can use to protect their plants, officials said. At the earliest stage, the insects can be washed off with a high-pressure water spray, and oil applications and commercial pesticides can eliminate the insects if sprayed thoroughly and often enough, officials said.
Still, Pam Thibodeaux, an Alamo Heights resident who has found evidence of the scale on about half of the 20 palms in her yard, said she may be forced to replace sagos that die with something else.
"It's pretty devastating," Thibodeaux said.
Copyright (c) 2006, San Antonio Express-News
This message was edited Apr 19, 2007 6:15 AM