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11-16-2016, 08:30 PM
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Jr. Member
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Join Date: Nov 2016
Posts: 8
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White spots and rotting on Cymbidium?
Hello, just registered and making my post right away, I'm sorry for not checking the forum for existing threads regarding this situation.
I've bought a cymbidium a year and a half ago. It had a spike and it bloomed already.
A month or more ago I started to see these white spots on some leaves coming from one particular pseudo bulb. Now these spots climb higher and spread out to adjacent leaves. Photos are attached.
Also, some of the youngest leaves on a different pseudo bulb are very light colored, are thin, have problems going upright and are yellowing starting at the tops.
What am I dealing with?
I was planning to split the plant in two, should I transplant the bulb that has the white spots? Should I transfer the dead, dried pseudo bulbs as well?
Thank you very much.
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11-16-2016, 10:13 PM
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Senior Member
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Join Date: May 2008
Zone: 9a
Location: Nor Cal
Posts: 26,634
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I can't be certain, but it looks like those spots might be mealy bugs. Look closely at them - mealy bugs often look fuzzy.
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11-16-2016, 10:26 PM
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Senior Member
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Join Date: May 2015
Posts: 351
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I would say it looks like the Hawaiian snow scale (or whatever it's called)
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11-17-2016, 12:26 AM
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Senior Member
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Join Date: Jun 2015
Zone: 9b
Location: Phoenix AZ - Lower Sonoran Desert
Posts: 18,645
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Welcome to the Orchid Board!
It's an insect infestation. You must treat it rapidly or they will kill the plant rapidly. You need to isolate this plant away from other plants, too, or it may spread to them.
Use the Search function in the top maroon menu bar to search on Cymbidium and Scale.
Cymbidiums don't do well unless you keep at least 3 or 4 pseudobulbs together when you divide. Don't divide plants going into winter. They have a hard enough time without that trauma. Insect-infested plants don't root well and don't grow well.
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11-17-2016, 03:17 AM
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Jr. Member
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Join Date: Nov 2016
Posts: 8
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Thank you VERY much for your answers.
So I looked into scale, and people are advising two types of treatment; using either rubbing alcohol or bathing the plant in soapy water.
Any particular preferences?
I won't be dividing the flower yet, however, since it's getting tight in its pot, I want to at least repot it. Can I do it now or should I wait until the scale problem is resolved?
Once again, thank you for your help, ladies and gents.
Stanislav
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11-17-2016, 08:26 PM
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Senior Member
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Join Date: May 2008
Zone: 9a
Location: Nor Cal
Posts: 26,634
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For scale, I have cleaned plants well with rubbing alcohol a few times. I spray well, one leaf at a time, wipe well with a paper towel.
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03-21-2017, 01:58 AM
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Jr. Member
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Join Date: Nov 2016
Posts: 8
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Hello again, dear members.
I have to "revive" this thread once again, since the same plant is causing problems.
So the scale situation is somewhat under control; it keeps coming back every once in a while, but not like the infestation I had originally. By checking the plant every 2-3 days, if there are any,I clean the appearing scale with alcohol swabs, but it DOES come back.
I did repot the plant in October 2016, and after that the plant seemed to be stunned; nothing was growing, I had a new small bulb growing since September, and it kind of stayed the same size. Someone advised me to stop watering the plant so the root system would be stimulated to grow.
I did not water the plant for one month, which in my opinion, DID help - I have some visible roots that appeared on the surface, and even got what seems to be a new spike (see attached photos). The young bulb is growing as well, albeit extremely slowly.
I water my cymb, and my other 4 orchids (phals), every two weeks; for example, water on saturday, then give them fertilizer (25/10/10 or 15/30/15,depending if flowering or not) two days later. Is this method OK?
My phals seem to do just great, growing roots/leaves/budding/flowering like crazy.
However, the soil mix in cymb seemed to still be moist after 2 weeks, so should I water less frequently?
Another problem, after I start to water the cymb, I have these black spots appear, more and more lately, on the leaves (see rest of the photos). Before, they were only close to the base, but after the last time I watered the cymb, almost 3 weeks ago, there are a whole bunch of spots that appeared on the leaves, closer to the tips. All affected leaves grow from the same bulb.
-So what is happening, and what should I do?
-How often should I be watering my cymb?
-Is there another, more permanent way to fight the scale?
Please help.
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03-21-2017, 06:59 AM
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Senior Member
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Join Date: Jul 2012
Zone: 8a
Location: Athens, Georgia, USA
Posts: 3,208
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two subjects here.
Pests: You either need to use a systemic insecticide, or plan on dabbing the plant with alcohol every 2 or 3 days while it slowly declines. In the USA, i would use imidacloprid or acephate. Ask around at garden centers and see what _SYSTEMIC_ pesticides are available to you. Isolate the plant or your other orchids and houseplants will soon be infested.
Watering. IMO, once every 2 weeks is not nearly enough. Frequency should be closer to a thorough drench twice a week.
I also agree with the opinion not to divide your plant. Minimum 4 pseudobulbs per division when dividing. Also, most people only divide when wanting to propagate a plant to share or sell - you shouldn't do either until the insect infestation is completely GONE for 2+ months.
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03-21-2017, 07:12 AM
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Senior Member
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Join Date: Mar 2015
Zone: 10a
Location: Abrantes
Posts: 5,538
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I've used imidacloprid based insecticide on cymbs to treat conchinilha.
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03-21-2017, 10:35 AM
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Senior Member
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Join Date: Nov 2008
Zone: 9b
Location: north florida
Posts: 3,384
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think about the environment that the 'pest' loves....and avoid creating that.....scale love hot dry conditions!
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spots, bulb, white, pseudo, leaves, ago, cymbidium, upright, attached, yellowing, light, starting, thin, colored, dead, dried, transfer, bulbs, transplant, dealing, photos, tops, plant, split, planning |
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