Looking for good online resource for orchid diseases...

though maybe it's here!

I have a gorgeous orchid that i got from my grandmother's greenhouse -- I'm sorry to say i didn't photograph it while in bloom, all i can tell you is it is not from the phalaeonopsis family and does not have pseudobulbs. the flowers grow about 8-12 apiece per stalk and started out purple and faded to white before withering....really stunning.

anyway. when i got it, i noticed brown, raised splotches on the leaves. the splotches are firm and are about the size of a tictac, or larger. any idea what these are, if they are harmful to the plant, and if so, how i can deal with them?

thanks much!

My guess is Pythium ultimum (black rot) on an oncidium. The first thing to do is take a razar blade and get that leaf off of the plant and out of the area. Step two is isolate the plant. Step three is sprinkle a little cinamon on the freshly cut wound. Step four is treat the plant with a protectant fungicide like Truban. Water splashing on fungus like this spreads it from leaf to leaf and plant to plant. Also sterilize tools and pots and use clean potting materials. Finally, begin to treat the plant with a systemic fungicide like Subdue or Bayleton.

Jim



























truban

hi jim, thanks!

should i cut the whole leaf off, or just remove the black parts?

I would take off the entire leaf.

Jim

Question, where do you buy these systemic fungicides? Thanks

Any good garden supply store should have them. They're not hard to find.

Jim

Yes, I have the dreaded fungus. Your recommendations are right on. Black rot is easily spread by splashing water and poor air circulation. I am hoping since truban and subdue are so much $$$, are you interested in splitting with others to provide better deal for all? So appreciate. Also would consider turban, teterazole.thanks

You might consider Bayer 3 in 1 concentrate. It is easily available, reasonably priced and addresses a host of problems including insects, bacterial and fungal.