/ Register

Welcome to OrchidsForum.com. We are a friendly online community for Orchid Growers all over the world. If you haven't joined yet we invite you to register and join our community. Hope to see you on our forums!

Masdevallia Leaf Spotting

Discussion in 'Issues, Disease and Pests' started by nodrog6, Sep 29, 2019.

  1. Sep 29, 2019 #1
    nodrog6

    nodrog6 New Member

    Messages:
    17
    Likes Received:
    8
    Location:
    Redondo Beach, CA
    When I bought this orchid in spring 2018, the seller said that the plant had gone through a massive heatwave. It's a Masdevallia coccinea x caloptera. For the past year, it grew very slowly until recently it put out several medium sized leaves. The oldest leaves stuck around staying yellow or green/yellow.

    Today, I noticed that a newly opened leaf is spotted . Could this be a virus or something I need to worry about? Thanks!

    IMG_1539.jpg
    59146966821__F98A0E82-810A-4FD8-8A02-26B40F8D44A9.JPG
     
  2. Sep 29, 2019 #2
    Antonio :(:

    Antonio :(: Member

    Messages:
    37
    Likes Received:
    0
    Does the black spots go into the leaves?
     
  3. Sep 30, 2019 #3
    Marni

    Marni Well-Known Member Staff Member Supporting Member

    Messages:
    13,779
    Likes Received:
    3,577
    Location:
    Santa Rosa, CA
    Bean Yellow Mosaic Virus is the most common virus in Masdevallia and shows up on the emerging growth. But that color on the newest leaf doesn't look like BYMV. Also, the patterning is somewhat symmetrical which wouldn't be virus. There is one leaf that looks questionable and that is the one close to the base of the plant that has a curve to the center rib of the leaf. When I was acquiring a lot of masdevallias I used to see some plants that had curved midribs or a twist to the midrib or an odd pitting on the surface. They didn't always have BMYV (which is obvious to spot once you know it) but they never looked "right". It turns out that at least some of the time, it also had Odontoglossum Ring Spot Virus. Bad water quality (sodium in particular) can cause the leaves to go yellow. If it was from that you should repot into fresh medium as some things don't wash out. You might try dosing the plant with epson salts to see if the leaves green up.

    Once the leaves look like a ripe banana as some of yours do, they are no longer photosynthesizing and can be cut off. Be sure to use a sterile blade.
     
  4. Oct 1, 2019 #4
    nodrog6

    nodrog6 New Member

    Messages:
    17
    Likes Received:
    8
    Location:
    Redondo Beach, CA
    Antonio: The black spots are surface level.

    Marni: Thanks! I'll cut those old leaves off and try an epson salt bath. It's had RO water since I originally repotted it. At what point would you test for ORSV or destroy the plant out of fear of something spreading to other plants?
     
  5. Oct 1, 2019 #5
    Ray

    Ray Orchid Iconoclast Supporting Member

    Messages:
    1,831
    Likes Received:
    596
    Location:
    Oak Island NC
    What is your feeding regimen?

    The few dark spots could be nothing more that infections begun when water sat on the leaves, but the first thing that popped into my head when I saw the photo was a deficiency of some sort, possibly magnesium.

    Most household water supplies contain plenty of calcium and magnesium, but with RO they must be supplemented regularly.
     
  6. Oct 1, 2019 #6
    Marni

    Marni Well-Known Member Staff Member Supporting Member

    Messages:
    13,779
    Likes Received:
    3,577
    Location:
    Santa Rosa, CA
    I use RO water and feed constantly. You can starve your plants literally to death if you don't fertilize regularly. I would keep the plant quarantined until you have more new growth and see if it grows normally. Some pleuros don't test for virus but always look wonky. I personally think that those may have a virus we aren't testing for.
     
  7. Oct 1, 2019 #7
    nodrog6

    nodrog6 New Member

    Messages:
    17
    Likes Received:
    8
    Location:
    Redondo Beach, CA
    I water/fertilize weekly. First I flush with RO water (< 10 ppm), wait about 30 mins, then water with about half a liter of MSU RO fertilizer at 150 ppm, 6.0 pH.

    Could that be too little fertilizer (amount or concentration)? Do plants in brighter light need more fertilizer than plants in lower light? A few of my other masdevallias at the same brightness level have more green/yellow leaves, but I had attributed that to light.
     
  8. Oct 1, 2019 #8
    Ray

    Ray Orchid Iconoclast Supporting Member

    Messages:
    1,831
    Likes Received:
    596
    Location:
    Oak Island NC
    I think you can improve your feeding regimen a bit, as you are definitely underfeeding.

    First of all, a MSU RO solution with a TDS of about 150 ppm means you're feeding at a nitrogen concentration of only about 25-35 ppm N. Then, on top of that, you're saturating the roots and medium with plain water first, limiting their ability to absorb fertilizer later.

    If you flood the pot with a fertilizer solution at every watering, it pretty much takes care of the need to flush separately, although it pays to do so with plain water about once a month anyway.

    Secondly, for feeding only once per week, you should probably apply a solution 3- to 4x that concentration. 2.1g/L or about 1/2 teaspoon/gal is a good figure to use weekly.
     
  9. Oct 1, 2019 #9
    nodrog6

    nodrog6 New Member

    Messages:
    17
    Likes Received:
    8
    Location:
    Redondo Beach, CA
    Thanks Ray, that's great info. I'll flush less frequently and up the concentration.

    Most of my plants are masdevallias, draculas, and small New Guinea dendros. Should I increase the fertilizer concentration slowly as I would changing lighting? Also, I have several mounted orchids that I spritz daily. Does it matter if I spritz with RO daily/fertilize weekly, or should I make a weaker fertilizer concentration and use that daily? Thanks again.
     
  10. Oct 2, 2019 #10
    Ray

    Ray Orchid Iconoclast Supporting Member

    Messages:
    1,831
    Likes Received:
    596
    Location:
    Oak Island NC
    I am an "EOA" (equal opportunity abuser) of plants - nothing gets special attention.

    Before I moved and downsized, my greenhouse irrigation system had fertilizer metered in at 25 ppm N (about 1/6 tsp/gal for MSU RO), and everything got that every time I watered.

    The frequency was determined primarily by the weather. If it was warm and sunny, that could be every day or two. When the weather started to "gray up" and the plants slowed their growth, that was less frequent.

    How potted or mounted didn't matter.
     
    nodrog6 likes this.