The alcohol and 409 works although I like more alcohol in my mix. I have it mixed up all the time. If you are repotting hose off the old mix really good and spray the mix on the leaves and psuodobulbs really well and use a toothbrush to get in the tough spots and brush the whole plant, remove all the old sheaths, hose off, spray again & scrub. Be a careful around the dormant eyes & really I don't spray the roots. Once it's repotted I use a sticker and put it on a leaf to remind me to do a checkup. Respray all leaves & bulbs again about a week later. Those little buggers like our heat
I've been buying the alcohol at Costco, comes in a 2 pack.
The reason I asked what they are on is that my oncidium leaves don't like the spray so much but I have not had any problems with them for a while.
Good Luck.