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Pale bleached older leaves: Aerangis species

Discussion in 'Issues, Disease and Pests' started by xmpraedicta, Aug 1, 2022.

  1. xmpraedicta

    xmpraedicta Prairie angraecoid nut Supporting Member

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    Hi all,

    I have two species that have puzzled me. I first noticed older leaves getting pale and chlorotic mid 2021. I initially suspected a nutrient issue, and it still very well could still be that, as my 2021 growing season I wasn’t entirely consistent with fertilization. Starting in February 2022, I’ve been regularly using MSU at 0.25 tsp per gallon to provide roughly 50ppm Nitrogen and water mounted plants every other day. PH is adjusted to 5.5-6

    I started fertilizing more regularly as the Aerangis distincta was growing it’s leaf first new leaf of the season. The leaf started nicely green, which was encouraging, but now that it’s matured and new leaf is emerging, it too is starting to develop a pale character. It’s as if there isn’t enough nitrogen or chlorophyll to go around.


    43C66A9C-F444-4C3C-9459-8EBB02C0D9E9.jpeg
    1. pale older leaves 2. First leaf of the season - started growing in February was nice and green now demonstrating some fading 3. Current leaf that’s growing

    323315D8-69C4-41AF-86D9-A05BF5E34998.jpeg
    Aerangis arachnopus showing similar


    Any advice? Is 5 months of supplementation not long enough to see results? At one point I also suspected too much light, but I don’t believe this is the case because they are growing in shade, and even the shaded parts of the leaves are pale. I started supplementing with a bit of magnesium a few weeks ago. However, with these species being generally low-nutrient requiring plants, I’m a bit puzzled by all of this. Am I being inpatient and should carry on as is?
     
    Last edited: Aug 1, 2022
  2. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    How old is your MSU? I got a batch in June of 2019 that caused lots of different problems and I lost 15% of my collection before I figure out what was going on. I would try using another fertilizer for a while. With in a couple of weeks using another brand, I saw lots of roots start to grow. I had almost no root growth for a year and a half before with that batch of MSU. I am not saying that MSU isn't a good fertilizer, just that there was a bad batch that they didn't admit to.
     
    J E likes this.
  3. Ray

    Ray Orchid Iconoclast Supporting Member

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    Seems unlikely to be related to the MSU formulation, as the issue began before you started using it. However, it still could be nutrition related, since your feeding regimen was admittedly inconsistent. (I did that not long after relocating, with similar results.)

    What is your water source? Have you tried supplemental Epsom Salts to boost the magnesium? We’re the plants exposed to a pesticide in that time frame?
     
  4. xmpraedicta

    xmpraedicta Prairie angraecoid nut Supporting Member

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    Thanks Ray - I was hoping you would chime in.

    I use reverse osmosis water. The filters are due to be changed, but my last TDS reading showed 8ppm so I'm hoping it's not that. I started some epsom salts 2 weeks ago so probably not soon enough to see results. I previously tried some Calmag, but honestly found it very challenging to gauge how much to use and I saw some burning so I stopped. Any recommendations on amount of epsom salts to use if watering daily/every other day? No pesticide use for over a year.

    EDIT - I just read your helpful site which recommends 20-50ppm Magnesium. With my 50ppm N MSU, I'm probably only getting 7ppm of magnesium. I will be supplementing with epsom salts continuously immediately.

    Thanks Marni - I'll switch things around and see how things go. I have another newer bag of MSU that I will try. It may very well be the same batch, as we buy it in bulk as a society, given that it's not economical to purchase it in Canada. I'll do some digging to see what brand we've been using to keep track, if anything.
     
    Last edited: Aug 2, 2022
  5. Ray

    Ray Orchid Iconoclast Supporting Member

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    Epsom Salts do not need to be fed continuously, as the mineral is easily translocated throughout the plant. 1 teaspoon/gal monthly is probably sufficient, although I have applied as much as 1 tablespoon/gallon without negative effects.
     
  6. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Calvin, As I look at the pictures again, the roots look really healthy and the plants in the background look very good. Is this the only A distincta you have and have you had it long? Is it happening to any other plants? I wonder if it could just be this particular clone.
     
  7. xmpraedicta

    xmpraedicta Prairie angraecoid nut Supporting Member

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    Thanks Marni - I have a newer Aer. distincta that is much younger that's fine, but I've only had it for about 6 months. However, I have this happening with Aer. arachnopus and a bit with Aer. biloba as well, all of which are older (>4 years) plants in the collection, which makes me feel it might be a related nutrient issue.

    Good to know!