Disease and Disorders

[fred]

I hope this information helps

Unfortunately, along with the pleasure of seeing your orchids come to bloom, there are a few negative aspects to orchid growing such as disorders and disease.
Most orchid sicknesses are preventable by proper growing conditions. We hope you never encounter any of these.


Basal Rot
Basal rot is commonly known as 'Southern Blight'. It is directly
related to watering methods and practices. Either overwatering, or water left standing in the crown of plants combined with cool humid situations can bring on this condition.

On soft and broad leaved orchids there is little warning. Basal rot, as the name suggests, starts at the bottom or the crown of the plant and proceeds upward. Therefore, by the time you notice a problem, it is already too late. If the condition is discovered on a plant with multiple growths, and only a small portion is afflicted, you can attempt to save the plant by cutting away the diseased portion with a sharp knife and treating the wound with sulphur. Keep on the dry side after the "operation" and hope the rot does not spread.

Botrytis
This is a fungal disease which affects primarily the flowers of phalaenopsis,
cattleya, cymbidium and dendrobium. This condition occurs most frequently in cool, moist conditions where there is little air movement. Symptoms are tiny black spots on the petals which soon grow larger and in extreme circumstances are covered with a grey fuzzy mold. If caught early, take measures to increase night time temperatures to no less than 65 degree F and provide maximum air circulation.

Remove and destroy badly infected material such as dead flowers which have fallen to the floor and are covered with mold. Spray flooring with a strong solution of fungicide. This will not reverse the damage already manifest on your bloom, but should dry up the affected areas and halt the further spread of spores.

Fusarium Wilt
Its a disease in itself, but rather a common affliction due to poor culture or
growing conditions. The most often contributing factor is severe shortage of water, especially during the growing season. This is evidenced by extremely shriveled, desiccated leaves. The whole plant is noticeably suffering and appears grey in color. Overwatering can produce the same symptoms once the roots have rotted and can no longer provide moisture to the plant.

Remedy: Pull the plant out of the pot. If there are no live roots, give it a decent
burial because it will not be worth the time and effort spent to attempt a resurrection. If in the early stages however, and if there are still some viable roots present, you can attempt to save it.

Repot immediately in fresh moist orchid seedling mix. Put the newly potted plant in a more subdued light than where it was growing and keep the mix on the moist side, but not wet. Mist once or twice a day to help humidity. You may see no improvement at all until the next growing season when the plant will attempt to put forth new growth along with a new root system.

Pseudomonas Cattleyae
Pseudomonas cattleyae, also known as 'brown wet spot' occurs mostly in phalaenopsis. However, a similar wet bacteria infection can occur on other orchids as well.

Plants develop brownish black, soft areas usually starting on the underside of the leaves and quickly penetrating to the leaf surface. This affliction is a destructive rot which can spread with amazing speed, taking in the entire plant within only a few days. The cause is a combination of cool temperatures, high humidity and inadequate air movement. Prevention is easier than the cure. Keep minimum night temperatures around phalaenopsis at least 60 to 65 degrees F, along with brisk air circulation. Brown wet spot can not develop
under such conditions.

Remedy: If the disease has reached the crown portion of the plant, there is no
cure even if some of the leaves look healthy. On phalaenopsis, if caught early, the affected leaf should be cut off (well below the afflicted area) with a new razorblade or some other sterilized cutting tool. Wet rot on other orchids must be treated by lancing and then cutting and/or scraping out the damaged tissue.

Dust the cut surface with sulphur or a good powdered fungicide. Lacking these, you can use regular mouthwash, applied half strength. Try to rapidly dry off the injury by placing the plant before a fan. Isolate from your regular growing area to prevent any spread on the disease.

Virus
This is the most dreaded orchid disease because it can not be visually identified in its early stages. Orchid virus disease invades and kills leaf cells which condition in turn facilitates secondary bacteria infections. The disease has no preference to type or genus and can spread from plant to plant indiscriminately by insects or cutting implements. In the advanced stage,
orchid leaves will display ugly black rings, circular or diamond shaped spots.

With the exception of the tell-tale black spots on the leaves, some plants appear otherwise normal and continue to produce normal spikes and blossoms. Unfortunately, there is no remedy or cure for orchid virus and the only positive way to know if your plant is infected is through laboratory testing. There are many other causes for black discoloration on orchid leaves and that condition in itself does not necessarily mean that your orchid is infected by virus.


Maintaining consistently clean growing conditions along with common sense cultural practices including optimum temperature and climate, will go a long way towards keeping your orchids healthy and in top condition.

[Cynthia, Prescott, AZ]

Fred, I am of the understanding that Fusarium Wilt is definitely a desease, and a very deadly one at that, and should not be confused with wilting because of loss of roots. Fusarium wilt generally leaves a red lining under the outer layer of tissue along the rhyzome, and excising the bad tissue means cutting until there is no more red visable. I have had a few cases that I suspect was fusarium wilt, with a strong red caste on the leaves, or perhaps a related desease, which was extremely deadly. I have recently arrested the problem in a young plant using Phyton 27, with repeated spraying several days apart.

The comment about it not being worth trying to save plants that are rootless should be read as Fred's opinion, and not one I share at all. I have saved many a plant without roots, and it is well worth while, especially for a favorite plant that is not replaceable.

On the subject of virus, my reading indicates that the only insect that has been proven to transfer virus is aphids, which harbor the virus within their mouth area somewhere, and inject some kind of juices into the plant as part of the process of eating.

[Richard Butt]

Fred,
Recent purchase of an Onc. had black spots on the underside of leaves near the tip. I sprayed with Schultz's "Fungicide Plus"(Myclobutanil and Permethrin are the active ingredents). Do I continue to spray every few days until the spots are gone?
Advise,
Richard

[nita cabangis]

I have several orchids and some of them have these white sticky tiny things scattered at the base of their leaves under and over. At first I wiped them with tissue and really cleaned them, so I thought they are gone and my orchids will be safe. But again they're back, this time I repot them and replace new soil mix and dry bark and hoping again that they will be alright. I don't know if this white things are what you called mealy bug. I and my orchids need help. I don't want to lose any of them as much as possible but I am not expert with orchids. Any advice will be gladly appreciated, and thank you all.

[Rocinante]

Originally Posted by nita cabangis

I have several orchids and some of them have these white sticky tiny things scattered at the base of their leaves under and over. At first I wiped them with tissue and really cleaned them, so I thought they are gone and my orchids will be safe. But again they're back, this time I repot them and replace new soil mix and dry bark and hoping again that they will be alright. I don't know if this white things are what you called mealy bug. I and my orchids need help. I don't want to lose any of them as much as possible but I am not expert with orchids. Any advice will be gladly appreciated, and thank you all.

Nita, go to Home Depot and get some Insecticidal Soap...follow the directions on back.

[aacor]

"To help control orchid "rots," dissolve 1 tablet of aspirin in 1 liter of water, drain off liquid, and mix at a 1:10 ratio dilution in water, spray on plants". Orchid List Digest

[LouisW]

Nita Carbangis-the sticky drops on the leaves of your plants are probably whats called "honeydew". It is produced when unsavory insects on your plants excrete exess sugars. if you taste them and the drops are sweet, thats why. The droplets are not the problem themselves, if you look above the area where the drops fall you may see a colony of mealybugs, scale, or aphids. aphids can be banished by soapy water but the other two may need harsher chems.

[davetheorchidaddict]

Fred,
Thanks for the information, a refresher is always good because it gives the memory that sudden jolt. Thanks

[kb5916]

Hi, I am new into orchids and my Phalaenopsis seems to have a problem. The flower petals on my white Phalaenopsis have very small white stains, that become tiny little holes as time passes. My Phalaenopsis is new (my wife gave it to me as a present!!!) so I am not fully convinced whether or not this stains were caused by the transportation of the plant!!

Thanks in advance for any help! Any advice will be most appreciated!

(p.s. I'd like to say that I'm writing in a forum for the first time, so don't get me wrong if my post isn't where it's supposed to be.)

[Ron]

Hi Fred A very good subjest to bring up.
Basal Rot, Botrytis and many other fungal diseases can be controlled by just adding a couple of good fans and if indoors, maybe open a window to let in fresh air.
Avoid watering in the morning or on cold days.
Many people forget such simple cures.
Take for example Phalaenopsis, I have about 100 or so plants ranging from baby's to mature plants.
I water overhead every water day, fertilizer over head ever fertilizer day.
I have been seriously growing them for about nearly 4 years now and never lost a plant.
I never spray preventive chemicals on any of my plants and do not get any sort of rot.
Just plain simple good plant husbandry.!
As for virus plants, only buy from reputable nurserys or good growers with a good reputation, avoid flea marketts etc.
If you supect a plant you have is virused, it most like is so put it in a bin.
Good growing
Ron

[tyunpefyl]

I am of the understanding that Fusarium Wilt is definitely a desease, and a very deadly one at that, and should not be confused with wilting because of loss of roots.



Edited] Fusarium the links in your signature have been deleted
please do not replace them as they are considered as spam
thank you

[kmarch]

Fusarium Wilt is actually a fungal (Fusarium oxysporum) infection, usually of the roots inhibiting the plant's ability to take in water, thus the wilting symptom.

[Celcat]

Could we have pics? I think it will be nice if we could have pics for each identified disease or disorders or even pests. I know most of us has books with some examples, but they are not always a exhaustive list. Of course we could always search on the net for pictures, if but we could build a kind of database with pictures for orchids disease and disorders, I think it would be a very useful tool

[Stitz]

Originally Posted by Celcat

Could we have pics? I think it will be nice if we could have pics for each identified disease or disorders or even pests. I know most of us has books with some examples, but they are not always a exhaustive list. Of course we could always search on the net for pictures, if but we could build a kind of database with pictures for orchids disease and disorders, I think it would be a very useful tool

Great idea, Celcat!

FWIW, I had a silver maple tree that died from Fusarium.


--Stitz--

[lenete28]

Im just new in orchids. I have this beautiful orchid but it starting to have weird crinkle spot and some dark spot on leaves. pls. could you help...

[kmarch]

I'm afraid the pics are too blurry for me to be able to clearly tell what it is.

[sunshine]

From what I could tell in the first 2 pics is it looks like the leaf is starting to dehydrate. How often do you water? Since this is a phal have you checked the roots? The 3rd pic. That dark coloring on the leaves is normal for a lot of phals.

Here is a culture sheet for your phal. Learning the proper culture and care is the first step to a healthy, happy orchid

AOS | Phalaenopsis

[lenete28]

i water them once w week, thats what they told me when i bought phal, im afraid for her to die. im so glad to know this site, peope who are willing to help for people like me.

[Marisa]

Hello everyone from sunny Greece!
I am new in the forum and also quite new in the area of orchids. I've loved them since very young age but I only recently had the chance (and conditions) to purchase some (3 phalaenopsis, one cymbidium and a very sad vanda ...).
While my phals and cymbidium are great, they grow wonderfully, with big leaves and beautiful flowers, I have problems with the vanda that I so much love...
I've tried to find on the internet people facing the same problems as me, but I didn't find someone facing the exact same problems. This is how I found your forum and I signed in.

So, to the facts...
I have the Vanda for about 1 month. Its roots are in a basket and the whole plant in a glass vase. From the first week its leaves started turning a little yellow. Because the weather was hot, I kept it at first on the veranda, on a spot with direct sun light only for 1 hour in the afternoon. All day long nice indirect light, and temperature around 25 degrees Celsius. I watered it twice a week and sprayed a little bit every morning just to add moiture. It didn't look happy and I was told that I shouldn't keep it outside so I placed it by a window with again light all day long and a little direct sun around 5 o'clock in the afternoon. I stopped the spraying with water and watered the plant once per week. The situation worstened: the already yellowing leaves turned so yellow that they look almost white, and they are soft too. Also, I had some fungus on those same leaves. I sprayed the plant yesterday with a fungicide (antracol). Before spraying antacol I cut off the yellow leaves with the fungus, and now the plant has leaves only from one side.
I think that the yellowing is continuing and I do not know what to do... However, the roots seem to be fine!
I am starting to think that maybe the water spraying harmed the plant from the beginning... I really love this plant and have prepared a lot before purchasing it. But I think it is dying, and the worst thing is that I do not know what harms it...
I am sorry for the size of my post, but I am very troubled with this situation...
Thank you very much for reading...

[zaeem]

I have givenup on vandas!!

Experts please advise.Thanks
zaeem

[zaeem]

my Phal bottom leaves are showing yellow on half leaves,,growing in a bathroom with light but no indirect sun.Do I need to expose it to shaded sunlight?Or is it diseased? Maybe drop leaves,I will be left with 3???
Please help.Thanks.
Another dropped all leaves,and is leafless I am keeping it with only roots potted.Confused.
Zaeem

[zaeem]

[zaeem]

Some thing going wrong! Any advice/Please.
Thanks
Zaeem

[PocoGigio]

Are you getting water in the crown?

[dounoharm]

hmm, looks like you have some leaf rot going on....when you water do you wet the leaves some? and do you have enuf air movement around the orchids? they need a lot of air circulation....i would repot that phal and try to get the roots going down in the medium....gl

[zaeem]

no water in the crown of phal ,trying to recover a wilted plant,for a month,now yellowing etc.
Thanks.
zaeem

[zaeem]

Duonoharm.
Thanks perhaps repot again in bigger mix.Iuse coco small.
zaeem