How effective is physan?
 

From your experience, how effective is physan in treating orchid rot? More specifically, black rot and soft mushy rot that seems to come back even after cutting. And yes I follow the sterilization and air circulation "rules" but :(.

Also, how effective is physan when sprayed on healthy plants as a preventative? I'm having orchids that looked great a few days ago and now they're rotted away.

I hear it mentioned a lot, but I've never used it. I also heard from people that it's not strong enough to deal with rot, so I'm not sure if I should just skip it and go on to use Phyton 27?

Where is the best place to buy phyton 27?

Sounds like you need Phyton 27. Physan 20 is a good disinfectant and preventative.

Take a look at this link for a comparison of the two: http://www.avsa.org/Library/20%20or%...r%20Phyton.pdf

I got mine online at kkorchids.com. They won't mail it if the temperature gets too low.

Preventative is better than cure in my opinion, I think as soon as rots set in you are on to a losing battle to recovery and these products are of little use apart from to limit the spread.
Better to do a periodic spray, this goes for using pest/disease control products.
So many people get the products out as a cure, I alternate between two pest/disease products and spray mist with Physan when I remember, and it is due! so thanks for reminding me. We cannot get Physan in the UK so I will probably have to look for a alternative.

I had no luck treating rot with Physan.
Phyton, however, did work.

Hi,
One thing that works very well on rot caused by bacteria is hydrogen peroxide. A 3% solution like at the drugstore works very well.

Physan and hydrogen peroxide are topical treatments - i.e., they will kill what they come into direct contact with. Physan is an excellent preventive disinfectant.

Black rot (caused by fungi of the genera phytophthora and pythium) is a systemic infection, so will not be significantly affected by either of them; you need a systemic fungicide.

Phyton 27 is systemic, but the active ingredient is copper sulfate, which can be used as a herbicide, so some plants - notably dendrobiums and some "thin leaved" genera - do not do well with it. I recommend Cleary's 3336WP for a systemic fungicide.

Incidentally, if this is a recurring problem, it suggests your growing area is significantly contaminated, so a general dousing with Physan is probably in order.

Ray, I'm finding Cleary's 3336WP is discontinued. What's next best? After reading your comment, I canceled my order for Phyton 27 so I could order Cleary's. What took the place of WP?

THANK YOU!!

Check your growing conditions. Plants aren't that susceptible to various infections if temperatures and relative humidity are correct.

I was concerned about that myself, then out of the blue about 3 weeks ago, a long back-order of Thiomyl (generic Cleary’s) showed upon my doorstep.

I’m away until next week, but you can grab one now to secure it for shipment.