Quote Originally Posted by Dorsetman View Post
You must be very cautious with any new chemical treatment. Orchids are sufficiently different from other plants for it to be unsafe to make assumptions.
Older growers will remember Malathion which is a superb bug killer, and maybe harmless with sympodial orchids but fatal to some monopodials, in particular phalaenopsis - it caused the growing point to turn into a flower bud, so that the treated plant never grew another leaf...
And then there was the infamous Benlate - cured fungal infections, but killed so many young orchids that du Pont ended up with 7 figure payouts ( not to me or you, of course, but to the big producers of orchid seedlings ). and tge effects became visible only some time after absorption into the plant tissues, making it diffucult to pin-point as the cause.
So beware using the new wonder mass murderer of all pests until it has been tested, and trsted again and time has passed...
Personally with rather more than hundreds of orchids of very many kinds and genera, I find mass treatments expensive and unsatisfactory. Spot treatment - when I see a pest I stop what I. Am doing to deal with it - and for most things a quick spray with alcohol/warer 50-50, and mabe a sweep with a clean artists paint brush kept on every bench for the purpose, to get the stuff unto the nooks and crannies and sweep away any debris or eggs/nymphs. If is is scale, then the Neem mix instead, but actually, the alcohol works with them too to some extent.
I agree with you, Geoff, that one has to be terribly careful. Triazicide has been around for awhile and is advised as a treatment for all sorts of bonsais. Granted, they're trees and not orchids, but I first tested it out - extremely diluted - on an orchid that was in the throes of death from mealy bugs and nothing else had worked. I would caution that I always wear gloves, I apply it outside, and it's a last resort. I usually use the preventive strategy of mixing a bit of Physan about once a month when I water. I find neem oil to be messy and ineffective by the time I see something on my orchids that needs taking care of - I do use it mixed with lemon juice to clean the leaves before a show.