Physan 20 for Erwinia?
User Name

Registration is FREE. Click to become a member of OrchidBoard community
(You're NOT logged in)

menu menu

Donate Now
and become
Forum Supporter.

Physan 20 for Erwinia?
Many perks!



Fauna Top Sites
Old 10-24-2022, 08:40 PM
MateoinLosAngeles MateoinLosAngeles is offline
Senior Member

Join Date: Oct 2022
Member of:AOS, OSSC
Location: Los Angeles, CA
Posts: 148
Default Physan 20 for Erwinia?

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.
Reply With Quote
Post Thanks / Like - 1 Likes
Likes realoldbeachbum liked this post
Old 10-25-2022, 09:21 AM
Ray's Avatar
Ray Ray is offline
Senior Member

Join Date: May 2005
Member of:AOS
Location: Oak Island NC
Posts: 14,224
Physan 20 for Erwinia? Male

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.
Ray Barkalow, Orchid Iconoclast
Try Kelpak - you won't be sorry!
Reply With Quote
Post Thanks / Like - 1 Likes
Likes realoldbeachbum liked this post
Old 10-25-2022, 11:54 AM
estación seca's Avatar
estación seca estación seca is offline
Senior Member
Physan 20 for Erwinia?

Join Date: Jun 2015
Zone: 9b
Location: Phoenix AZ - Lower Sonoran Desert
Posts: 16,384
Physan 20 for Erwinia? Male

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.
May the bridges I've burned light my way.

Weather forecast for my neighborhood
Reply With Quote


erwinia, orchid, physan, plant, quantum

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Physan 20 and Polycarbonate BrassavolaStars Beginner Discussion 1 09-30-2019 08:30 AM
Mixing Physan 20 Solution with Orchid Food Solution bethanyarmstrong Beginner Discussion 7 09-10-2013 07:41 PM
Using Physan 20 Pilot Semi-Hydroponic Culture 22 07-21-2009 09:10 PM
QUESTION - Using Physan 20 in ALL greenhouse water ? EdinAZ Greenhouse Gardening 7 04-05-2009 02:09 PM
Algae control with Physan and bleach terryros Semi-Hydroponic Culture 11 06-08-2008 01:36 PM

All times are GMT -4. The time now is 09:03 PM.

© 2007
Search Engine Optimisation provided by DragonByte SEO v2.0.37 (Lite) - vBulletin Mods & Addons Copyright © 2023 DragonByte Technologies Ltd.
Feedback Buttons provided by Advanced Post Thanks / Like (Lite) - vBulletin Mods & Addons Copyright © 2023 DragonByte Technologies Ltd.

Clubs vBulletin Plugins by Drive Thru Online, Inc.