I've never had that issue, Ecko fears no noises. Air compressor, gun shots, nothing. Sometimes I think it might be that he is a little "special". LOL!
Maybe start her in the house while the bug zapper is going, and work your way out and towards it. Hopefully she picks it up quickly. Is she afaid of storms? The dogs I used to house sit for were, we played loud movies like Top Gun during storms and never had a problem. Not sure if that helps with the bug zapper bit though. My fingers are crossed for something working for you.
No she's not afraid of storms it's just the zapper. My other rescue jumps at it to (I'm like whar can you hear there screams!?!) But not my Cheza, she is completely freaked. Starting inside is a good idea. Guess it's time to bust out the raw hamburger meat again. Lol
Yes my two not rescues are find, nothing fazes them, but the rescues are very soft. Super sweet but very soft.
Ha my neighbor has one and I thought Jack would freak out when he heard it but he doesn't seem to be scared of it at all and now just ignores it. He's a little more worried about being attacked by a butterfly or a bird lol.
Is she scared of the zapper while it is off? Or just when it is on?
If she is scared of it while it is off then just take it down and let her see it maybe?
I haven't heard of dogs being scared of a bug zapper before but my bosses pit Daisy will run and hide if you pick up a tazer. Which she was probably abused and zapped with one before they got her. But my own boy Jaws isn't scared of the Tazer at all, he tries to go after it after it makes the zap noise.
The noise might just be sensitive on her ears, or just startle her? I agree with starting her off in the house while it's on. Or maybe just leave it on for a long time, like day and night. hearing the constant zapping might not be so scary after a day or so.