Physan 20 for Erwinia?

[MateoinLosAngeles]

I've never had to deal with Erwinia but when a friend showed me his orchid I noticed what clearly seemed an Erwinia brown spotting on the leaf which was wet underneath.

My first thought is to treat with Physan 20 and then with Quantum Orchid. The Physan 20 label indicates that it's effective in the treatment of Erwinia, following these instructions:

Concetration: 1 tbsp Physan 20 per gallon of water.

– Remove media
– Soak entire plant in Physan 20 solution for 10 minutes (I understand this is the entire plant including leaves, stem, roots, and not only the affected part)
– Cut away rot with sterile tools.
– Soak plant wounds again for 10 min (I understand e.g. for Erwinia you would only soak the part of the leaf where you made the cut)
– Repot in Physan 20 soaked media

Some online resources mention Physan 20 as a sufficient treatment for Erwinia. Most resources, however, highlight copper products and I've found contradictory information regarding the efficacy of Physan 20 on Erwinia, and of course many DIY pages suggest trying Hydrogen Peroxide 3% from the drugstore.

Following the treatment with Physan, I would probably put some cinnamon on the cut and on the next watering soak the media and spray the plant with Quantum Orchid (or nowadays I use Quantum Total which First Rays sell at a competitive price). Then spray with Quantum daily for a week.

For some reason I find contradictory information on the uses of Physan and some opinions contradict the label. If anyone could chime in and share their suggestions on the use of Physan or some other treatment, that'd be very helpful! We might be able to save my friend's orchid.

[Ray]

Physan is a topical disinfectant. It will kill erwinia (pectobacteria) on the surface, but will have little effect on the systemic (internal) infection.

Oh. It will also kill all of the bacteria in the Quantum product, rendering it useless, and will do so for about 2 weeks after the Physan treatment, even with adequate flushing.

Copper treatments, being systemic, will generally be better for treating the disease, but I’d do so immediately, and resume the Quantum in a few weeks.

[estación seca]

The first priority is cutting off infected areas if possible.

Also fix the growing conditions. Erwinia is usually a disease of high temperatures, high humidity and low air circulation.