Guignardia fungus prevention?

[Jayfar]

Does anyone here find their Neos are susceptible to the same Guignardia fungus, characterized by black leaf spots, that seems to be very common among Vandas generally?

None of my Neos have any significant spotting, most none at all – YET, but it's pretty likely that my small number of Vandas all have Guignardia fungus present to some extent, unless the tiny black spots are something else entirely. I'm a little concerned that if my Vandas do indeed harbor Guignardia that they are likely to eventually pass it to my nearby Neos, which of current necessity live very close to the Vandas at the moment (they'll be moving across the room in the winter). I had already removed the worst spotted lower leaves from my 2 biggest Vandas.

Would it be a good idea to use a preventative treatment of Cleary's 3336F. I've seen some recommendations to alternate Cleary's or any other systemic containing thiophanate methyl, with a non-systemic such as Mancozeb.

I generally prefer to use chemicals as little as possible, but on the other hand I do want to minimize any risk to my Neos, since they're all about the foliage.

So I'm putting the question out here to the experienced long-time Neo growers. What are your experiences regarding Neo susceptibility to Guignardia and other nasties and what, if anything, do you use as preventatives?

[Jayfar]

I also found a good article by Dr. Martin Motes, linked by Island Girl in another thread:

http://www.staugorchidsociety.org/PD...t-ThaiCrud.pdf

I don't think any of my Neos have the kind of spotting characteristic of Guignardia, but I certainly want to be proactive concerning anything that could ever affect them. On the other hand, I'm not so inclined to indiscriminately spray them with chemicals. At the least though, I think I'll start treating the Vandas with Cleary's.

On a happy note, I just today noticed a 2" spike on my V. Coerulea, which hadn't bloomed for me in the nearly 2 years I've had it. The spike is emerging from a growth that started almost immediately after the top of the plant was damaged by a rot a long time ago. The spiking keiki is near the top of the plant, not a basal keiki, and recently began putting out a fat branching root of its own.

[Jayfar]

Any thoughts? Are my worries of potential future problems largely unfounded?

Don't know what it is about them, but I seem to feel more protective towards my Neos than my Phals (of which I've killed my fair share).

[coffeecup]

I suppose since I have no idea what you're talking about, that must be a good sign as a fellow Neo grower. Quite honestly Jay, I'm not really sure myself.

The only issues I've had with my Neos are fungus gnats and other crawlies that decide they like living in moss mounds. In fact, I have a new bug that seems to love moss, but I don't even know what it is...just that none of my plants are in decline from it. For a minute, I thought it could be thrips, but my plants haven't been damaged at all, so that couldn't be it.

[NYCorchidman]

If you value your neos, then I would keep them all away from "suspicious" vanda that is nearby your neos. Then, again, the spores will travel freely in the air. once the leaves are wet, the spores germinate. plants can also fight off to certain degree.

The best thing to prevent is by not introducing any orchids that display the symptoms of the fungus. Once you do, then you have already brought in the trouble. This is highly contagious and hard to get rid of kind of stuff I read.

Also, not wetting the leaves will help.

Good light and watering, generally keep the plants strong, and strong plants generally fight off pathogens on their own unless you create unfavorable environment.

I got rid of some of my tolumnias that were near my neo for that reason. So far, three of my neos are spotless clean and I hope they all stay that way.

---------- Post added at 11:36 AM ---------- Previous post was at 11:33 AM ----------

Oh, one thing I read that some people do out there, is you cover the spots with clear nail polish. The idea is to prevent the fungal spores from being released into the air.

I'm not sure how effective it is, but it makes a lot of sense. The black spots are "young" stage and will not release spores. Once they are mature, the black spots will have tan colored center with some tiny dark center which releases spores.