Viruses and Infections

[Dave]

Some of the signs of viruses on orchid plants include: light brown or black spots on the lower and upper surface of leaves. Very faint at first and gradually they develope darker. Discoloration in flowers can occur as well.
Viruses can be transmitted via other infected orchids, tools not properly sterile.

Solution: As of today there are no treatments for viruses. The plant must be destroyed before it affects other plants in the growing area. If however you can not bring yourself to throw it out, isolate the plant by itself and continue to grow it that way.

[twirly]

However I wouldn't be that radical...isolation is a solution but killing the plant is never one

Orchids can fall foul of leaf rot, mildew, botrytis and many other pathogens, by and large, providing there is a good air movement around the plant, and that by nightfall the leaves are fairly dry, then fungal infections should not be a problem, and correction of the bad condition, along with a fungal spray (check with the garden centre that it is safe for orchids) should do the trick, a fast fix for a localized leaf infection is to dust a little cinnamon onto the infected area.

It is very difficult if not impossible to cure a plant suffering from a virus disease, because it's hard to identify which particular type it is, and most likely a useless exercise anyway, as viruses are almost impossible to cure, thankfully, providing you are hygienic around the growing area, and that any tools used on the plants are thoroughly sterilized after use between different plants, you should not encounter this type of problem.

[twirly]

For anyone interested Amazon has a large number of books, both new and used related to diseases and viral affections on plants. My recommandation, as a plant owner and lover are: "How to Control Orchid Viruses: The Complete Guidebook" by Gail C. Wisler ...I had the opportunity to look through it and it's quite on the point with the issue and "Orchid Biology" (Orchid Biology Series) by Joseph Arditti (Editor) because it gathers around the specificity and everything you need to know to success in understanding the rhytm of an orchid.

[orchidreamer]

Sometimes it's easy to get viruses confused with fungal spots. They both are "spots" and can look quite weird. Check for pictures on the internet--one thing I noticed about virus spots is that they form a sort of pattern. Sometimes they are parallel to the veins in the leaf. Just some observations.

[orchidaddict789]

If a plant looks suspicious then isolate it. I've heard of sending plant tissue to a special lab that tests for virus, but I don't see much point in it unless the plant is extremely precious and you're really worried.

[Dave]

Orchiddreamer I agree with you completely,

Sometimes it's easy to get viruses confused with fungal spots. They both are "spots" and can look quite weird.

When I was a newbie I thought all of my orchids had viruses lol..turned out some were just diseases which could/ can be prevented with a proper disease spray solution.

[Gin]

I have the name of a Lab. that does testing for around $5 per plant if you want the name PM. me.
I have no connection to the lab . Gin

[Cynthia, Prescott, AZ]

I've started a pbase collection of virus photos. Will up date as I get more pictures. I have been testing very old plants, and those that look suspecious. First round was positive in about 2/3 of the plants tested. BIG warning. Aphids transmit virus between plants. I am throwing out nearly my entire collection of reedstemmed Epidendrums because I had repeated bouts of ahids, until I found neem oil works great. All tested Epis came back positive for virus. Aphids love Epis. When I moved the Epis into my house, ALL of the aphids went with them. No residual aphids were left in the GH. If you can't be darn near perfect in bug control, get rid of the virused plants or keep them a LONG way away from your healthy plants. Cynthia

http://www.pbase.com/schnitz/virus_in_orchids

[orchid.gecko]

Originally Posted by twirly

However I wouldn't be that radical...isolation is a solution but killing the plant is never one

Orchids can fall foul of leaf rot, mildew, botrytis and many other pathogens, by and large, providing there is a good air movement around the plant, and that by nightfall the leaves are fairly dry, then fungal infections should not be a problem, and correction of the bad condition, along with a fungal spray (check with the garden centre that it is safe for orchids) should do the trick, a fast fix for a localized leaf infection is to dust a little cinnamon onto the infected area.

It is very difficult if not impossible to cure a plant suffering from a virus disease, because it's hard to identify which particular type it is, and most likely a useless exercise anyway, as viruses are almost impossible to cure, thankfully, providing you are hygienic around the growing area, and that any tools used on the plants are thoroughly sterilized after use between different plants, you should not encounter this type of problem.

Note to all: PLEASE cite where you are getting information from! I found this online (http://www.orchid.org.uk/orchidproblems.htm) on the North England Orchid Society website. It's important not to take credit of the knowledge if it was obtained from somewhere else!

[Gin]

If you look at the url. you will see where these came from . No links or pop ups that I could tell . They are not my pictures ,,, Gin

http://www.ionopsis.com/Pests_and_Diseases.html

[jerrymeola]

Newbies should not be overly worried about this thread. Viruses are controlled in commercial nurseies (usually by destroying infected plants). Viruses are not transmitted to seed grown plants from the parents but are inherited in cloned plants. A nursery with a virus problem does not clone the species its bad economics.

Especially do not be concerned about small black spots near the ends of Oncidium Alliance plants (vocabulary - alliance is used to indicate that the family of plants is roughly grouped with others as to care and growing characteristics, including intergenetics - intergenetics 2 or more families crossed)

The black spots are a common characteristic of the family and are harmless to the plant. They are usually called freckling.

Cattleya alliance are much more prone to mildew and bacterial fungus. Both are easily treated. If a large area, cut off the leaf. If a single plant, you can wipe with peroxide. Contact fungcides like Physan are not as effective as systemic treratments like Phytan27. Contact only kills what it touches and needs to hit both top and bottom of the leaf, systemics are absorbed into the plant and are effective longer.

These poisons are strong use gloves and wash after use.

[NancyG]

Where can you buy these products?

[Cynthia, Prescott, AZ]

Physan 20 can be bought from Calwest Orchid Supplies: http://www.calwesttropical.com/
I would not bother trying to find some Phyton 27, as it is extremely expensive, and not available at most Orchid Suppliers. I have gotten it at Hummert for $53 for 8 oz. It is so expensive that I don't use it regularly and the few times I have, I have not been able to detect any improvement in what ever the probelm was. Fungus spores are one of those ever present things, and the best defense is to grow the palnts with proper culture. Don't mist late in the day, and don't let plants get colder than is normal for them, or give them too much, or too little light, in order of importance. Healthy plants resist fungal infections. I use Physan 20 at a low rate in my fertilizer solution, but again, it is taken on faith that it is doing any good. If you use to much Physan, I can tell you from experience that there will be phytotoxicity, so error on the low side. Cynthia

[atcrosby]

Thanks Jerry for the post on the black spots on Oncidium Alliance plants. I hve one that has these black spots and started to freak out. I hauled the plant over to a grower and he just laughed showing me his oncidiums and sure enough they are healthy, growing and flowering even with those "freckles".

One thing about Orchids is that I am trying to keep them all going. They are surviving my amateur mistakes on watering and most species are thriving in my house. (Who would have thought?)

Now the stressful period begins as all of them finally drop their leaves to prepare for winter. Hopefully, I will see blooms next year! (Fingers crossed)

[Cynthia, Prescott, AZ]

I have updated my virus photo site, and included the type of virus in the caption. Note that these marks can often occur for other reasons, so these should be used only as indications that further testing might be appropriate.
http://www.pbase.com/schnitz/virus_in_orchids
Where I have my testing done:
http://www.crittercreeklab.com/

Many people grow virused plants and don't care about the fact that they are virused. This is fine for the casual grower, but be aware that virused plants can be difficult to grow, and that is the big problem. If your plants are growing well, don't worry about them. I not only test plants with symptoms, but those that seem to have repeated set backs. Just simply growing virused and non-virused plants side by side I don't consider to be a problem, except for the possibility of cross transmission by aphids. I think it very illuminating that with so many of my plants (>50%) virused by a stupid mistake 20+ years ago, there were still many orchids that had been sitting side by side in a very crowed greenhouse with the virused plants all those years and never were infected.

I think we can all take a fairly casual view of virus just so long as we always follow the most basic rules of orchid growing: Always used sterilized tools to cut into living tissue, watch out for jabbing plants with fingernails, use sterilized or new pots, and if you have to handle broken roots while repotting, use fresh disposable gloves. If you find aphids on a plant, in addition to spraying, preferably with neem oil, remove the plant immediately from the presence of the others and grow it separately for a month or two until you are sure that there will be no repeated infestations. My experience is that aphids love certain flowers or shoots, and will be found no where else.

Cynthia

[arleneg]

Cynthia, thanks for posting your updated orchid site. When I saw that pic of the cattleya with brown coloring on the petals, I knew that's the same thing going on with my Paph. Ho Chi Minh.

I lost the first bloom to it (spreaded within a matter of days; bloom turned all brown) and thought it was just stressed out from shipping. Well, I see the same thing happening to the second bloom. Since my paph. is sitting next to two healthy Phals, I'm trying to figure out where to place my Paph. I already have a Blc. and an Slc. separated from the healthy ones due to (now I know what they are after reading and seeing all this info on this thread) fungus, mealy bugs and scales. I've been treating those two orchids with PharmSolutions' Indoor Pharm w/Rosemary Oil. It works. However, my Blc. and Slc. get reinfected. My husband told me to cut my losses. But it's difficult to rid of them when one has a few pseudobulbs and leaves left that are still green; the other is all green and producing new shoots.

[Cynthia, Prescott, AZ]

Arlene, if they are being reinfected with scale, you are probably not killing the eggs. The mealies are probably coming up from the roots if you grow in an open mix like bark. I find that neem oil does a pretty good job on the eggs of scale, but still I had one kind of scale that I had to retreat every couple of weeks for several times. The mealies may require that you soak the pot in something for a few hours. I would not give up on these until your try the neem oil. Solving these problems is something you have to learn, so treat them as subjects for experimentation.

Don't worry about the Paph if you think it may look like virus. Symptoms could be caused by other things, and just sitting next to your other plants shouldn't be a problem anyway. Certainly, the change in environment can cause upset to the plant that could take months to get over, maybe even a year, so don't assume the worst just yet. Growing orchids requires enormous patience, so give that Paph a chance to acclimate in the best growing area you have. Cynthia