I finally got ahold of physan. I'm wanting to treat a couple of phals for fungus related issues. I've read the back of the bottle, but I'm wondering how strong can I go without any negative affects from this product?
These phals are not in the best of shape. I'm hopeing a couple of treatments will turn them around
Back of the bottle call for 2 teaspoons per gallon. The additional product insert calls for 1 tablespoon per gallon when dividing plants or treating for rots such as Erwinia
I want to echo what John said. I know of no problems using Physan - it seems to be a rather mild fungicide, but there were problems some years ago with Benlate - it caused deformation in plants and flowers when overused, and then there was a contaminated batch that nearly wiped out some of the Florida dealers that were using it regularly, which all adds up to "be very careful when using chemicals of any kind." Like meds for our use, more is not usually better, but they're best when used as prescribed and only when necessary.
And I'll echo what Ron said. Physan 20 is pretty mild if used according to bottle label directions. I have successfully used the strong mix (the one for sterilizing bench and pots) on orchids with no observable damage. If you are experiencing really advanced root rot or crown rot or rot spots on leaves, you should opt for a chemical such as Thiomyl or Phyton27 which are systemic to some degree. Physan 20 is safely used as an algicide helping to keep down algal growth in pots, and mold growth on outsides of pots. Be prepared for several applications - it's fairly weak - weekly, for 3-4 weeks. Be patient - it does finally work. Will also be effective (finally) on mold and mushrooms on moist mounts in an orchidarium. Just need to be diligent at applying every week for at least 4-5 weeks.
Thanks for you're advice guys. I try to stay away from any sorta chemicals, so overuse wouldn't be any issue. I think I've been pretty lucky so far, I've not had to deal with alot of problem orchids
Ross, I can no longer get the phyton 27 down my way. So it's gonna have to be the physan for me. I'll try a few treatments but I won't hold my breath for it to work.
Good luck. I have had reasonable success with Physan in control of mild algae issues as well as with spraying roots at repotting and spraying cut edges of plants without any signs of damage.
There have been some concerns and reports with using Phyton 27 in that damage with frequent use can result in accumulated toxins and damage to the plant.