Need help with the symptom

[frank_in_la]

I don’t think it’s caused by water left on crown. But I’m not sure. I’m worrying it is virus. Can anyone identify this? The fallen leave is the youngest leave.

[frank_in_la]

I use same water to fertilize a whole batch. I added epsom salt and liquid seaweed. Both 1/4 of the strength. Also my cymbidium turning black on the youngest plant.

[SouthPark]

frank ----- it could possibly help with assessments by providing some details about how the orchids are being grown. Eg. outdoor or indoor. Temperatures of the growing area, watering method. Any air-movement in the growing area, pot type, and details about drainage holes in the pot etc.

These following links could be helpful later. Click Here and Click Here and Click Here and Click Here and Click Here and Click Here

[Roberta]

Frank,
I doubt virus. It looks bacterial or fungal. The practice of sharing water/fertilizer water between plants is a near guarantee that any disease that one plant has, will spread to others. (Would you share a toothbrush with random strangers, or even your friends????) And I know that you have other plants with issues. Sharing water is a major no-no.

[Ray]

I agree with Roberta. More likely a bacterial or fungal infection than a virus.

Watering multiple plants from the same batch of solution is not a problem, but reusing the water is. I wasn’t sure which was the case from the original description.

[frank_in_la]

Thank you guys for the advice. I got a 1-gallon sprayer and will use it for fertilizing going forward.

The Phal. is one of three Phals I put outdoor as experiment. Night temperature dropped to 33F a few days ago. Last night it was 37F. Not sure if this also contribute to the issue. But the other two Phals are OK in cold night though. No sign of stress.

I'm more concerned about my cymbidium. I bought it last month and it's in bud. Should I use diluted Physan 20 in case it's fungi related? Will it hurt the roots?

[Roberta]

Cymbidiums outside where you live should be fine. If you want an example of "how tough" take a look a this link: Ice . Below 32 deg F. you might lose buds, but the plant will not be harmed. Don't worry about treating it.

Phalanopsis are a different story... that cold is enough to severely damage, or kill a Phal depending on how long it is exposed. A Phal right next to the house or a block wall that radiates a bit of warmth might survive, but continued exposure to that much cold is likely to be fatal sooner or later.

[frank_in_la]

Thanks Roberta. I don't know what's the root cause of the blackened area of cymbidium, as you said it's not cold weather. I'm just want to prevent it from spreading if it is fungal or bacteria damage.

[SouthPark]

frank ---- for the cymbidium ---- if the region is black coloured and dried out, then don't worry about it.

But if it's black coloured and spreading, and especially the same is occurring on other bulbs and stems, then some systematic treatment might be necessary - such as copper spray, or monterey garden phos etc.

Warm temperature and gentle air-movement and avoiding really soggy media and roots down in the dark depths of the pot ....... can certainly help avoid fungal/bacterial issues.

In my tropical conditions over here - with nice temperatures and air-movement and my usual watering method ------ I don't get bacterial or fungal issues at all.