UV light to kill bugs

[Discus]

The UV sterilisers Camille is talking about are different from the bug zappers - they're a germicidal UV bulb encased in a quartz tube (normal glass blocks UV), past which water is pumped; these units are invariably then inside an opaque tube as the UV is not in any way good for you. Similar units are used in the aquarium trade and in ponds for either killing algae or for germicidal purposes, depending on the flow rate, bulb spectrum and treatment distance. It's actually surprisingly hard to kill some things with UV, but almost everything will be zapped if the contact time is long enough/frequent enough.

[Connie Star]

It's hard to imagine that UV light intense enough to kill pests wouldn't also harm the plants. I believe they're intended for sterilizing things like water that you are going to then use on the plants.
I remember when I was a little girl there were some public restrooms that had UV lights that you flipped the toilet seat up into that were supposed to sterilize the seats. I have no idea whether it worked or not but it sure was fascinating.