How does rubbing alcohol kill bugs
 

We have ongoing problems with biosduval scale here. I usually control it with isopropyl alcohol. It’s made me wonder - how does the alcohol work. Does it poison, smother or something else?

Cheers
Arron

My understanding is that the alcohol breaks down waxy, protective layers, leading to desiccation.

If you have an "ongoing boisduval scale" problem, forget alcohol and do a treatment regimen with a "real" insecticide like acephate or imidicloprid.

KILL THEM BUGS! your orchids will thank you!

I would kind of wonder whether the orchid leaf also has a waxy or another membrane that can be "killed" by certain harsh chemicals. Hydrogen peroxide is well known for being a cellular killer, cytotoxic, and yet people throw it around on everything with wild abandon.

I have overused insecticidal soap and "washed" the cuticle off the orchid leaves. Ray is right, a good systemic will work best.