[orchidhelp] Re: "Thai disease" aka Guignardia and Phyllosticta

Wow! Thanks for the short-course. I've had some black leaves on a vanda but
I don't think they looked like that. And I grow Ascocentrums  with them
along with the hybrids with nothing like this.  Thanks a lot for the help.
I've used Phyton27 on several other things and it seems to work very well.
I've gone over to the high-priced spread for several insecticides simply
because they work. Get several comrades to go in on a bottle with you and it
doesn't hurt anywhere near as badly especially on the miticides. If you've
got cash, then don't worry about it just buy and spray. Service is also
great at http://growersupply.com/fungicides.html . Go to the home page >
chemicals and you can find the insecticides.

Gary

 

From: orchidhelp-bounce@xxxxxxxxxxxxx
[mailto:orchidhelp-bounce@xxxxxxxxxxxxx] On Behalf Of nancy
Sent: Friday, February 26, 2010 5:06 PM
To: orchidhelp@xxxxxxxxxxxxx
Subject: [orchidhelp] Re: "Thai disease" aka Guignardia and Phyllosticta

 


Not sure if I can attach a couple of photos, but I'll try. Info from the St.
Augustine Orchid Society's site (which has a truly excellent article on
pests and diseases, with gruesome photos) says, "The first signs of
Guignardia infection are tiny, dark purple, elongate lesions on either leaf
surface. These lesions run parallel to the veins and elongate into purple
streaks or diamond-shaped areas. spots often merge to form large irregular
lesions that may affect a large part of the leaf. With age, the center of
the lesion turns tan. Raised, black sporing bodies develop in the affected
area. Affects mostly Ascocentrumand Vandasand their hybrids and may indicate
insufficient light. This blight is also known as Phyllosticta; the names
apply to two different sexual stages of the same fungus."
The mature fruiting bodies give the leaf a texture very much like an emery
board.
I have been using Cleary's, among other potions. Was wondering if the nail
polish would actually help to save the leaf - it does seem to be decreasing
or absent in the newest foliage.
Hurricanes bring this stuff, I swear. A couple of our society experts
diagnosed it as mites, which I treated for for years. Wasn't.
Regards - Nancy

"Humor is reason gone mad." 
-------- Groucho Marx

--- On Fri, 2/26/10, Gareth Wills <gwills13@xxxxxxxxxxxxx> wrote:

 

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