Alright, this is going to be my last post on this issue. First, I would like to thank dollythehun for reminding me about "Zerotol" which is now sold under the name "BioSafe Disease Control." It is a contact fungicide of activated Peroxygen for the treatment of diseases on flowers, shrubs, lawns, fruits & vegetables. It is safe to
use on orchids. I still have a bottle of it and can list the active ingredients:
Hydrogen Peroxide 5.34%
Peroxyacetic Acid 1.36%
Other Ingredients: 93.30%
As to growing orchids, I have learned from much trial and error (and dead orchids) how to prevent diseases as I'm sure many of us have. One of the problems I previously had was crown rot in phals. It took me a long time to learn to grow them successfully without being infected by some type of rot.
Crown Rot is caused by Erwinia (Bacterial Soft and Brown Rots) or Pseudomonas (Bacterial Brown Spot). These are both opportunistic water borne pathogens which can kill a phalaenopsis within days. Both of these pathogens are easily spread by splashing water or allowing water to remain in the crown of a plant. Unfortunately, like most fungus and bacterial pathogens, they already exist on your orchids, in your greenhouse or growing area, pretty much everywhere and are just waiting for the opportunity to infect.
Of course, once your orchid has developed a bacterial infection, it is also prone to fungal infections and vice versa. The rot can develop anywhere on the plant so the idea is to stop the infection from reaching the crown and killing it.
Apparently bil has not had any problems with these types of diseases affecting his phals so he is definitely doing something right and, if I were him, I would not change a thing. However, I do beg to differ as to whether water can accumulate in the crown of a phal.
Whenever I accidentally get water in the crown of one of my phals, even if it's an hour later, I take the corner edge of a paper towel and slide it down at the bottom of the leaves where they form a cup to draw the water out. I keep doing this until the paper towel comes out dry. I even pull the edge of the leaf away and stick the paper towel down in there as far as I safely can because I often find water down in there.
The cup formed by the lower leaves holds water and does not self drain unless you use gravity to assist the plant in releasing the accumulated water. It is for that reason that I was able to eliminate diseases infecting my phals, I grow them with their pots tilted or even on their side making sure the crown is able to drain. Once I began growing them in this position, I have never had another disease affect my phals.
For me, I try to nip any infections in the bud because the treatment for crown rot is a copper fungicide. Most commercial growers of phals use a very expensive product called "Kocide." However, there are many orchids that copper fungicides cannot be used on because it causes toxicity within the plant. Personally, if I can take a chance and stop a disease with the occassional use of hydrogen peroxide over a systemic copper fungicide which treatment with can be more detrimental to the orchid than the disease itself, I personally am going to try hydrogen peroxide first.
I will end this post with the following from Al Pickrel, owner of "Al's Orchid Greenhouse",
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"Phals are highly susceptible to rots of all kinds. In nature most Phals grow on the sides of trees with their roots exposed to moving air and their leaves oriented in such a way that water runs off and away from the crown. Grown in a pot the opposite is true. Water collects in the crotches of leaves around the crown where most rots begin. Rots spread quickly and have usually killed or damaged the important growing tip in the crown before they are discovered. The most obvious symptom is leaves that turn yellow and blacken overnight. A closer look reveals necrotic, infected tissue at the base of the leaf where it connects to the crown or stem of the plant. If not stopped the pathogen will turn a healthy rapidly growing plant into mere compost in a matter of days."
It was after I read this article that I began growing phals in a tilted position and have been successfully growing phals ever since. Over and out.
Hydrogen peroxide
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