Plumie newbie seeking advice re: scale.

7 years ago

Hi everyone,

I'm new here and seeking advice on my small collection of plumeria. They all seem to have some amount of scale. Here is what I'm working with:

As you can see, they're indoors on a heat mat right now, as the nights are still too chilly here in northern NM. The two plants in front are both rooted. The large (6 foot) cutting in the back has failed to root despite multiple attempts, mostly because it's so unwieldy. Much to my amazement, it is still alive and strong!

This close up of one of the trunks shows the amount of scale I'm seeing:

On two occasions, I have sprayed the plants with a mixture of Dyna-Gro neem oil and liquid castile soap, but it doesn't seem like this has been enough.

I've already lost two other cuttings to the scale and figure I'll lose these plants as well unless I can find a way to get the upper hand. I haven't dealt with scale before and have been a bit discouraged by what I've read online. It sounds like it can be tough to control. This is where I need advice.

How far do I need to go to solve this issue? Do I need to completely repot the plants using new pots and soil? Or can I leave them as they are, and just make an effort to use the homemade neem oil spray on a more frequent basis (say, weekly?) until things are under control? Are there any other measures I should consider?

Re: the large cutting, I've decided to cut it up and make several smaller plants, since it has proven too unwieldy to root as it is. Would it be safe to spray the pieces after they've hardened off, but before I attempt to root them? And will they tolerate being sprayed while they're in the process of rooting?

Two of these plants have some sentimental value to me, but if necessary, I would be willing to dispose of them and start fresh with new cuttings. But, it would be nice if I could save them.

Any advice from growers with more experience would be much appreciated.

Many thanks,

Jennifer in Santa Fe

Featured Answer

floral_uk z.8/9 SW UK

7 years ago

Yes. I should have suggested the scratch test before. We often get queries about 'scale' which turns out to be lenticels.

I don't really see them as gross. Annoying, yes, but nothing intrinsically ugly or disgusting imo. If they were four feet across and endangered you'd be saying what a beautiful turtle shell.

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Comments (11)

floral_uk z.8/9 SW UK
7 years ago
Rather than spraying, try wiping with a baby wipe. Grasp the whole stem in your hand and rub up and down. The stems are leafless and fairly unbranched. It shouldn't take too long to wipe over the whole plants. Do it again after a week or so. Repeat until there's no scale left.
Jennifer B thanked floral_uk z.8/9 SW UK
Jennifer B
Original Author
7 years ago
Thank you for this suggestion.
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floral_uk z.8/9 SW UK
7 years ago
last modified: 7 years ago
You're welcome. This tip was given me by a professional citrus grower here in th the U.K. They (citrus) have to grow under glass here and scale is a big problem.
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the_first_kms2
7 years ago
I have used Neem oil and physical removal with a wet cloth.
tropicofcancer (6b SW-PA)
7 years ago
I doubt those white/brown dots are scales. My plumies have those and they do not scratch off. They are part of the stem. It is hard to see from the pic you posted but you should do a scratch test - if they are hard to take off then they are not scales.
Jennifer B thanked tropicofcancer (6b SW-PA)
Jennifer B
Original Author
7 years ago
tropicofcancer, your comment is interesting. I tried the scratch test as you suggested, and also looked more closely at the dots. Some do seem to be part of the plant, but others look different (more oval shaped and brown) and do scratch off more easily. I'm assuming the latter are scale. Glad to know there aren't as many as I'd originally thought.
tropicofcancer (6b SW-PA)
7 years ago
If you have a hand lens look at them carefully while still on the plant. They have a definite pattern on their outer coat. The actual insect is inside. If it is alive, when you scratch you will see a tiny bit of liquid ooze out. The brown ones are mature, may be empty too, you will feel it crack when you scratch. Here is a close up pic of scales. I saved this from another post where someone posted this pic. Pretty gross -huh.
Meyermike(Zone 6a Ma.)
7 years ago
Gross!!
tropicofcancer (6b SW-PA)
7 years ago
I do not find them gross either but I think quite a few do. Quite the opposite - I find them fascinating. I have an old style microscope that I use to look at this wonders of nature. Just bought a usb microscope so that I can take pictures too but have not had a chance to use it properly.
Jennifer B
Original Author
7 years ago
After taking a closer look, I figured out that most of the dots were lenticels. A few did seem like scale, though. They were more oval shaped and scratched off easily. Now I have a better sense of what to watch for. Thanks for the helpful comments.

@ tropicofcancer: Your comment made me remember how much I loved playing with the microscopes in my high school biology class. I loved to bring in flowers to dissect and study. Seeing them up close, I appreciated their beauty even more.