Just dropping in my limited experience with antibiotics on orchids.
I have found Agristrep (impure streptomycin) effective and non-phytotoxic on phrags to control basal rot. This is a rot that appears (at least in South Carolina) during the hot summer months, begins at the base of the outer leaves, and can quickly destroy a plant. I have no idea what the organism is.
Your MD won't have heard about it unless s/he's also a farmer as it is available from agricultural supply houses.
I too am concerned about the 'willy-nilly' use of antibiotics, but the problem there is parents who stop giving whining, uncooperative children their antibiotics as soon as the external symptoms abate (and do the same themselves when they get their child's new & improved bacteria). S. pneumoniae - the cause of most children's ear infections - is the same organism that kills the sweet little old people each winter when we have our pneumonia epidemics. (Kathy - I'm not trying to 'flame' you & I would definitely not use or recommend one of the newer '-mycins' destined for humans on plants)
David Janvrin
_______________________________________________ the OrchidGuide Digest (OGD) [EMAIL PROTECTED] http://lists.orchidguide.com/mailman/listinfo/orchids
