Help! Dendrochilium has yellow and brown spots on leaves. Is this a virus?
 

Hi all
I recently bought a Dendrochilum from a local green house. It had leaves with brown spots with a yellow outside rim. I originally believe it was due to sunburn, but I was told to ask you guys, the experts for advice on if this may be a virus. I was potted in moist orchid bark and I reported in sphangum moss.

Any advise, diagnosis and tips are appreciated

Thanks
newbieplantlover

It’s definitely not sunburn. It does look like it could be viral, but wait for a second opinion.

The only way to know for sure if it's a virus is to test the plant. However, it might very well be a fungal or bacterial disease, so I'd start with a systemic fungicide like thiomyl. If new leaves are disease-free, you know it wasn't a virus.

I'd have suggested a systemic fungicide/bactericide like Phyton 27, but my understanding is that it's toxic to coelogynes.

The yellow rings around the dark spots scream bacterial/fungal to me but Ray is right...only way to know for sure if it's viral is by testing.

If it were mine...I'd pick up some Serenade and give that a try. I nearly lost a den to something fungal or bacterial. It was mild before the plants went outside in the spring but w/all the rains and humidity we were getting early this year...it took over the plant fast. I removed the plant from the pot...cut off all the affected leaves (I was left w/only a couple of leaves) and potted it into new media then I sprayed the entire plant...soaking it well, including drenching the media...4x at 7-10 day intervals. All the new leaves are now coming in clean. The couple of leaves that were left did develop some spotting in the week after the first treatment so I cut those back...all new leaves are coming in spot free and so far...so good w/no new spots. I'm keeping a close eye on it and am prepared to continue treating, if necessary, but it looks good for now.

Obviously, there are no guarantees w/the Serenade...I've read some really mixed reviews on it but, for me, I figured I had nothing to lose because if I didn't do something I was going to lose the plant and it was my awarded Den Hibiki. My first AOS award!...I didn't want to lose this plant. As a matter of fact, if it had been any other plant...I likely would've just pitched it because it was so bad. Who knows...it could be worth a shot to give it a try.

BTW - it says it's just a foliar spray but I also drenched the media. It was fresh media but you can never remove every single piece of the old stuff so I drenched the pot also...just in case.