Orchid Insect and Disease Control-Part 1→Cymbidium Leaf Markings

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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
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Australis
Nov 23, 2017 11:35 PM CST

Plants SuperMod

I thought I might add some photos I have taken of various leaf markings on Cymbidium leaves and their causes in order to help others diagnose possible problems with their plants. I have updated this entry a few times as more information has become available to me and I've taken more photos. All virus testing has been done by the DPIPWE lab in Tasmania, Australia.

Insect Damage
The particular plant shown in this photo had a few scale insects on it when I obtained it (apparently the grower had had a bad season for scale). It tested negative for viruses.
Thumb of 2017-11-24/Australis/c0d883

Scale insects tend to hide under the old leaf husks, so even if there are few (or none) elsewhere on the plant, it pays to remove the old husks and keep the plant clean. Otherwise you might end up with a serious problem! Here's one that I neglected for a while and eventually noticed a number of insects on the leaves, prompting me to clean it up. These scale insects had set up quite a colony under the dead leaf husks:
Thumb of 2019-07-07/Australis/632009

Mites can do damage to both the top and underside of leaves. The ones I have encountered most tend to feed on the underside of leaves and create a pattern of fine speckling. If this becomes widespread, the underside of the leaf takes on a white or silvery appearance. The first photo below shows heavy mite damage, whereas the second shows moderate.
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Sunburn
This is the early stages of sunburn, which tends to occur on the highest point of the leaves (usually where they arch).
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Windburn
Some species and hybrids, such as Cym. erythrostylum and Cym. dayanum, have tender foliage and if exposed to windy conditions, especially when humidity is low (which can happen in winter in Australia), the bulbs and foliage suffer windburn. The plant shown has erythrostylum as one parent.
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Water Quality Issues
Some Cymbidium species are really fussy about their water quality (i.e Cym. devonianum, Cym. erythraeum, Cym. iridioides and Cym. tracyanum). They tend to suffer leaf tip dieback and necrotic spotting on the last part of the leaf. This particular plant is iridioides; it tested negative for viruses. The grower remarked to me that this is a common issue with the species. Note that the leaf mottling is a separate issue and not likely to be related to water quality.
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Cold Damage
Many of the traditional Cym species and hybrids will tolerate a light frost, but the warmer-growing species and hybrids will struggle with exposure to freezing temperatures. Below is an example of a canaliculatum that suffered extreme cold damage whilst being shipped to me - it lost a number of leaves, much of the root system and one of the new growths dessicated and easily came away from the plant.
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Environmental Mottling (aka Chlorotic Bleaching)
It seems that temperatures on the extremes of what a Cymbidium can tolerate may induce leaf mottling. This is not temperatures that are hot enough to cook the plant or cold enough to freeze it, but close enough to the edge that they start to have a visible impact on the plant. C. Mausteller writes on his blog about the impact of high temperatures on his Cymbidium collection; his devonianum hybrids in particular showed similar mottling as a result of exposure to temperatures around 43-44°C. At this time, I am not sure if other factors can also cause these symptoms.

Both plants in these photos tested negative for viruses.
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Hail Damage
If you keep your plants outside and they are not protected from the elements, then depending on where you live you may eventually encounter hail damage. I only get serious hail once or twice a year; in the most recent case, all my plants that were not quite fully protected suffered leaf damage on the exposed side. Note in the photos where the hail has "chipped" away at the leaf surface (interestingly, very few leaves were actually bent or otherwise damaged).
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Odontoglossum Ringspot Virus (ORSV) Symptoms
This is what ORSV can look like on a Cymbidium. I thought these photos were particularly important to include, as I have found it difficult to find good photos of ORSV symptoms online (perhaps because it can be variable). All of the plants pictured below tested positive for ORSV and were disposed of.

Chlorotic markings are a common symptom with ORSV. Note the chlorotic patch that is close to the end of each leaf in the first image below; the leaf on the left is showing the underside and has a much larger mark than on the leaf on the right. Occasionally the chlorotic markings are quite large, as shown in the second and third photos.
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I typically find that only a small number of leaves exhibit necrotic markings as a result of ORSV (the severity of ORSV symptoms can vary significantly and in one case I had, the plant was asymptomatic - which is more likely to occur if the plant is being well cared for). So far, the necrotic marks have followed a trend of being linear and running down the middle of one half of the leaf - not down the centre fold of the leaf, nor on the edges. Note that the marks shown are sunken and different to the necrotic spots on my iridioides. There is also some mottling around it, although not as obvious as the leaf tips.
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Another grower I have spoken with reported the ORSV can also cause v-shaped markings on the leaves. I have only seen this once on a plant (shown in the photo below), which tested positive as expected:
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Orchid Fleck Virus (OFV) Symptoms
December 2019 finally provided me with a good example of OFV symptoms on a Cymbidium (this plant tested positive). The marks can become necrotic, but in this particular case most markings were just chlorotic in nature.
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Cymbidium Mosaic Virus (CymMV) Symptoms
Unfortunately I have yet to see any confirmed symptoms of this virus. I have only once had a plant test positive for this and it was asymptomatic!


Multiple Viruses
It is possible that a plant can be infected with multiple viruses. To date, I have only encountered this once and it was a plant of Cym. iridioides that had both OFV and ORSV. Note the necrotic spots on multiple leaves, yet the majority of the foliage was still clean:
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Unidentified Fungal Damage
I have not identified the specific fungal infection here, but another grower did confirm that it was fungal in origin and the plant tested negative for viruses. It received two applications of a fungicide (Mancozeb) and all the new growths have been spotless.
Thumb of 2020-05-15/Australis/6bd3fa Thumb of 2020-05-15/Australis/cb7394


Summary
I hope these photos help others to identify possible problems with their Cymbidiums! I am happy to try to answer questions where I can.
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.
[Last edited by Australis - Oct 30, 2020 1:39 AM (+)]
Give a thumbs up | Quote | Post #1591676 (1)
Name: Lin Vosbury
Sebastian, Florida (Zone 10a)

Region: United States of America Deer Region: Florida Charter ATP Member Million Pollinator Garden Challenge I was one of the first 300 contributors to the plant database!
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plantladylin
Nov 27, 2017 10:19 AM CST
Joshua, what a great photo display and very helpful in identifying orchid issues. Thumbs up I think it would be really helpful for novice growers if we could have a "sticky" at the top of the Orchid forum with information like this!!
~ I'm an old gal who still loves playing in the dirt!
~ Playing in the dirt is my therapy ... and I'm in therapy a lot!


Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
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Australis
Nov 27, 2017 4:25 PM CST

Plants SuperMod

Thanks Lin. There is a direct link to the parent article on the Orchids forum as well.
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.
[Last edited by Australis - Jan 30, 2019 7:34 PM (+)]
Give a thumbs up | Quote | Post #1593397 (3)

fano16
Jan 29, 2019 8:47 AM CST
Dear All.
my cymbidium going very badly. Is a 5 years old plant. Just repot 1 month ago. Leaves continue to get yellow and in 1 or 2 days and then fully brown. No linear necrotic marks.
Can it be dehydration? can it be lack on fertilizer (unfortunately never given).
Please let me know if there's a way to save it, I really need it.
Many Thanks

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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Jan 29, 2019 6:39 PM CST

Plants SuperMod

Hi @fano16 and Welcome! to the the site. Unfortunately you won't get much visibility here, so I'm going to copy your post over to the Orchids forum: The thread "Cymbidium Losing Leaves After Repotting" in Orchids forum
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Daeneryseilaine
Jul 16, 2019 7:52 PM CST
Hi can anybody help me what to do with my cymbidium cause the leaves do have small dots in it. I really dont know what it was and what to do.
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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Jul 16, 2019 9:09 PM CST

Plants SuperMod

Hi @Daeneryseilaine,

Welcome! to the site. I'm happy to try to help. There's a few different possible causes for this (environmental damage, fungal spotting or virus), so if possible, can you answer the following, please?

Some more photos of the plant overall and some of the other leaves would be useful.

Also, does this spotting affect:

1) just a few leaves on the plant
2) all the leaves on just one growth/bulb
3) most or all of the leaves on the plant?

Do the youngest growths show any spots?

Do you know if the spotting suddenly appeared and if so, when?

Where is the plant kept - for example, does it get exposed to the elements (wind and rain)?
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 10, 2021 11:53 PM CST
Is this from hail damage? I was gifted 2 cymbidian orchids a week ago and both have this on their leaves, they were also sitting in inches of water!!! I know they were outside and we have recently have a hailstorm here, it wasn't a super crazy one though, and also it snowed here for a few days too...
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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Feb 11, 2021 3:02 AM CST

Plants SuperMod

Welcome! Kaiaadie

Yes, from the photos you've provided, it does look like hail damage (not particularly severe, though). The marks will remain on the leaves, but the plant will be fine. You won't want to leave them sitting in water, though, nor in the snow (they don't like freezing temperatures, although many Cym hybrids will tolerate near-freezing for a night or two).
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 12, 2021 5:39 PM CST
Could the cold weather and sitting in rain water to long cause black leaf tips and black spots on the under side of the leaves?
Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Feb 12, 2021 6:32 PM CST

Plants SuperMod

Cold weather can definitely cause leaf damage, although I'd need to see a photo of the black spots to be able to suggest possible causes for those.

The black leaf tips (leaf tip die back) can be caused by a few different things:

- Not enough water
- Too much water leading to root death, so then the plant can't draw up enough water
- Impurities in the water (some species and their hybrids need clean rainwater for their foliage to be clean, otherwise they frequently suffer leaf tip dieback; this can also be caused by excessive fertilising causing a buildup of salts in the pot)

Depending how long the plants were sitting in water, you may find the root system has been damaged. If the plant is allowed to dry out to ensure root rot doesn't establish (this'll make it look worse before it gets better), then the root system will recover in spring when the plant produces new roots.

What media are they potted in?
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 13, 2021 12:25 AM CST
I'm not sure there's much media in here...

I'll post pictures after I get the roots to come apart, its soaking now, they are soooooo compact I will destroy them if I don't loosen them first...
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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Feb 13, 2021 1:53 AM CST

Plants SuperMod

Those are some very healthy root systems! I would definitely recommend slip-potting into the next size pot (should have about half an inch to an inch of space around the existing root system) and filling in with some orchid bark.

I also recommend removing the old leaf husks around the bulbs. The couple of white spots on the dead leaf husks might be scale insects, but the rest of the plant looks clean. Removing all the old leaf husks will remove any hiding places for them as well as allowing you to check that the bulbs are still healthy.

The only thing I can see that concerns me is possible discolouration of two of the bulbs, which I have circled in this photo:

Thumb of 2021-02-13/Australis/0dc9df

If either of those pseudobulbs feel soft/squishy, then it is rotting. Given how solid the root system is, I would not try to unwind or divide it; I would just get a sterile blade (flame it or soak it in alcohol, bleach or trisodium phosphate for 20+ minutes) and cut out any bulb that is rotting, then allow the plant to dry out thoroughly before watering again.
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 13, 2021 3:03 AM CST
I got a little ways u to breaking up some roots to get the media out and cutting dead mushy roots then seen your comment and just potted it then, I circled some white spots, could they be scale? If it is, is there a one time treatment?
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Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Feb 13, 2021 5:40 AM CST

Plants SuperMod

The new pot and media look good - as long as it doesn't sit in water, it should be happy in that pot now. I'm still a bit concerned about that one bulb I can see that looks discoloured, but if it's still firm, it may yet be okay.

You are right that the dead roots will be soft; they will feel hollow, whereas the live roots will be firmer. I couldn't see a significant amount of dead roots in the photos, but they may have only just died due to sitting in water and not had time to turn black yet.

Regarding the white spots - if they are scale, they will be juveniles and you should be able to wipe them off easily with a piece of damp paper towel. The adults are harder to remove and I use isopropyl alcohol on a paper towel to wipe the leaves and the same on cotton tips (q tips) to get into the base of the leaves where they can hide. Make sure you wipe every leaf just in case. Overall the foliage looks pretty clean, so if you do have scale it's been caught in time. Once you've given the plant a once-over, check it weekly to see if anything's appeared. It may take a few iterations to get rid of any scale (I usually find it takes two passes over a couple of weeks when scale appears on my plants).
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 13, 2021 6:28 AM CST
I got a little ways u to breaking up some roots to get the media out and cutting dead mushy roots then seen your comment and just potted it then, I circled some white spots, could they be scale? If it is, is there a one time treatment?
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Kaiaadie
Feb 13, 2021 6:39 PM CST
I felt all the bulbs and none feel squishy at all so I left them all, thank you for your info, I have one more to repot and I need a deeper pot, the bulbs are almost an inch above the top of the pot I bought for it.
Name: Joshua
Melbourne, Victoria, Australia (Zone 10b)
Köppen Climate Zone Cfb
Region: Australia Bookworm Cat Lover Lilies Orchids Irises
Seed Starter Annuals Container Gardener Garden Photography Forum moderator Avid Green Pages Reviewer
Image
Australis
Feb 13, 2021 7:06 PM CST

Plants SuperMod

You are most welcome! Feel free to reach out if you have any more questions.

Good idea on getting a deep pot, as the bottom of the bulbs need to be into the media, otherwise the next growth emerges much lower and you end up with bulbs at all different heights, rather than them all growing in the same plane. Makes it difficult to repot in future!
Plant Authorities: Catalogue of Life (Species) --- International Cultivar Registration Authorities (Cultivars) --- RHS Orchid Register --- RHS Lilium Register
My Notes: Orchid Genera HTML PDF Excel --- Lilium Traits HTML PDF --- Lilium Species Crosses HTML PDF Excel --- Lilium Species Diagram
The current profile image is that of Iris 'Volcanic Glow'.

Kaiaadie
Feb 15, 2021 10:53 AM CST
I felt all the bulbs and none feel squishy at all so I left them all, thank you for your info, I have one more to repot and I need a deeper pot, the bulbs are almost an inch above the top of the pot I bought for it.

Kaiaadie
Feb 27, 2021 10:00 PM CST
They seem to be happier since repotting them, can anyone identify the new growths? New bulbs or possibly a flower spike?



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