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

  • From: nancy <platotoldhim@xxxxxxxxx>
  • To: orchidhelp@xxxxxxxxxxxxx
  • Date: Fri, 26 Feb 2010 14:06:05 -0800 (PST)

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 
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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