Brown soft blotch on ocidium leave-help!!!

[rick84]

Hello can anyone help me out. I have a oncidium Heavenly Scent "green valley D" (2). It is full of flowers and about 1 week ago I noticed this browning spot, since then it has become larger and is now slightly marking the bulb. Please help!!! Three attachments are the photo's for you.

[james mickelso]

Looks like anthracnose. A fungal disease that attacks the leaf turning it brown and soft like yours. Cit it off and dab cinnamon powder on the cdut edge. If it proceeds further then get a good anti-fungal spray or dip. Cleary's is good. Also go to the staugorchids site. .org I think. You will find what you are looking for there.

[rick84]

thank you very much for responding. I did have a feeling it was either fungal, viral or nutrient toxicity. This is curable, yes? When you say cut off the leave, you mean to cut off just the leave(s) that are infected. And where should this cut be made? At the base of the leave, or just enough to remove the fungal lesion? Im not sure if you can see the bulb in the picture that has the fungal leave? It too has a couple of spottings of this above spot. Should it too be removed to prevent this fungal infection from spreading futher down.

---------- Post added at 12:55 AM ---------- Previous post was at 12:25 AM ----------

I have a jug of DACONIL. Will that treat anthracnose? I use it on my blueberries to control septoria leave spot. It works pretty good.

[james mickelso]

Daconil should work. Cut off the leaf as this is an older pbulb and is finished growing.

[rick84]

Alright, I did tent to the leave. I used a #10 surgical scalpel and removed the diseased leave at the top of the bulb. I put daconil on a q-tip and like you would with cin, I dabbed it. Then I added some actual cin to the cut to help seal it. The daconil bottle doesn't "spray", it more less streams. So I applied it to the whole plant & spike (avoiding flowers, even though you can apply it to them without harm) using a q-tip to smooth or spread it. There is a large leaf in question here and I would like your advise on it. It at a average distance looks normally green, but when you look closer you can see it has a mottled light and dark green color. The tip of this leave has a necrotic patch and I am assuming that this is a progression of this fungal infection.

Also should I feed a B-vitamin and kelp to reduce stress and promote growth?

For some reason the site wont allow me to upload any pictures I took. Say I need to contact the administrator.

[rick84]

I just needed to resize them, now it works.

Pictures after surgery. Also should I be worried about this mottled leave. It has a dead tip that I sniped off.
.

[james mickelso]

I wouldn't worry about it. If you sprayed or drenched the entire plant then it may help if this is fungal. But there are lots of reasons that a leaf turns a mottled color. I've lots of them and it doesn't affect the outcome which are leaves and flowers. Just keep an eye on it.

[Island Girl]

This is a link to a PDF by the St. Augustine Orchid Society site (the one James referred to), and it has a chart w/ many bactericides & fungicides, and what they treat, and what they don't... This pdf is great help, and their main website is great too, very informative and with pics too!

PDF: http://www.staugorchidsociety.org/PD...idDiseases.pdf

EDIT: this is the main page, in the column on the left, under "Pests & Diseases" is a lot of great info, just pick out what section u wish to explore in the drop down menu that comes up. St. Augustine Orchid Society - North Florida Orchid Growing

[rick84]

thank you for helping james and island girl.