i purchased a cozumel and cancun cuttings last spring from the same source. they rooted quickly. they are healthy and growing nicely with about 16" of new growth since rooting.
there is one odd thing about both plumeria. they have these yellow spots. the pigment appears to be missing from the top of the leaves. none of the other plumeria in my collection have these spots. any ideas as to what's going on??? i thought that this might be some reminent from the previous owners fertilizing regime or how they are reacting to mine. like i said before, these are the only two plumeria in my collection that have these yellow spots and they came from the same source at the same time.
I would guess that is is a mineral deficiency of some sort -- perhaps an Iron deficiency. Is there something different about the soil that they are planted in? You probably won't be able to change these leaves, but you can help the new leaves coming in not to have these spots. I would add some Iron Chelate to the plants at watering time and see if that helps. You can also add two tablespoons of Epsom Salt to one gallon of water and see if that helps. I think I have seen this before once in a while on a sporatic leaf but never the whole plant. Do all the leaves of both plants have this?
there's nothing different about the soil. both of these plumeria receive the same treatment. that's what makes this odd. both plumeria are quite happy, healthy and green.
the yellow spots appear to be a systemic issue. i say this because no other plumeria in my collection have these spots. in addition, all the leaves except for the top 2 or 3 on both plants have the spots. in some cases the spots are "in focus" like those in the pic. in other cases they are large and diffused.
When i see that i think of two things..
Rust mites or a fungus which i seen do that down here..
Like Clare said it could be a deficiency too..
Next i would look at the location of these 2 plants compare to the others..
Are they in a different location? Are they next to another plant (non-plumie)?
Do they get less sun then the others?
Make sure now about the sun many peeps will answer yes they get full sun like my others..
I check my plumies yesterday and seen that my last row of plumies doesn't get anymore sun after 2:00pm due to the sun taking a more southern route now..
Rust mites are very hard to see you will need to get real close or throw some Ammen's
medicated powder on one of the leaves, the powder contains Zinc..
The powder will reveal the mites if they are there..
If no mites then i would use a foilar spray like SprayNGrow mix with a fungicide..
This should at least address 2 possible causes..
Like i said i seen this on a few of mine because of mites or a fungus (too much water not enough sun)..
Airflow is important because mites will infest a plant that doesn't get too much wind..
Speaking of spots on leaves, I have two seedlings that are about a year and a half old. They have rediish brown blotches on the leaves, some almost cover half the leaves. The seedlings appear to be very healthy and I do not notice any insects. I think it is a characteristic of the plants. Has anyone else seen this on other plants?
I'm not a plumeria expert so I'll definitely defer to Clare's opinion. One thing I've learned from growing lots of different plants is that symptoms in one plant that appear similar to another can be the result of very different causes. I did think "mites" on seeing the first picture. I've never had mites on my plumerias but then my climate is a lot more humid than AZ. Mites are tiny and very hard to see. One way to check is to rub a piece of white paper on the underside of the leaves (where mites usually congregate). If you see rust-colored or brownish/yellow stains on the paper, that's from crushed mites. Depending on the type of mites and severity of infestation, they can be controlled with neem oil spray or a miticide. (Even organic insecticidal soap will kill mites if they are not too bad.) Note that conventional insecticides are ineffective against mites as they are arachnids, not insects.
Tom, you are quite right, but I think usually the mite damage is a little different-looking. The damage tends to be concentrated more around the stem.
I usually struggle with mites here in this dry climate on my brugmansias and plumerias, but we had a very humid summer due to several tropical storms nearby, which came from the Gulf of Mexico. The mites have been scarce here this summer, and I think it is due to the unusual humidity. I even bought "Forbid" earlier this year in anticipation that I would be having a major infestation right about now, but there is no damaged evident. I've been pretty good about spraying the leaves when I water just to discourage them as they hate water. One of my plants in the corner of the greenhouse got them pretty good last winter. Here is a pic of what mite damage usually looks like for me in this climate:
What clare is showing you are spider mites indeed "not rust mites".
95% of the time people think it's a nutrient deficiency when in fact it's spider mite
You can use the method of the white paper as someone said..
This is the time for the rust mites hot dry weather late summer early fall..
Since we all can't inspect your leaves just assume it's all 3..
So with that said use a foliar spray mix with fungicide and sprayNgrow..
For mite treatment "DO NOT USE ANY OILS" !!!!!!!!!!!!!!!!!!
You are in AZ which is hot and dry and thats a NO NO for any type of oils..
If you use them you will kill the mites and your leaves with them possibly the stem too..
To treat rust mites use 1 of these 3 products..
Treating for rust mites requires using a miticide effective against eriophyid mites, such as Sevin, Joust, or dimethoate.
But you know what get yourself a 5 gallon bucket from home depot and use a capful of Hartz flea and tick shampoo mix with water and turn your plumie upside down and dunk her in the bucket and count to a 100 and set her back down on the ground and leave her alone..
I have done this to my thai peppers and plumie seedlings and it's been very effective and does not harm the plant in anyway...
Hartz flea and tick shampoo contains small traces of the same chemical that kills termites..
If you can kill a termite then you can kill anything..
Hope this helps!
Like Clare said read the FAQS at the top of this forum!!