Thanks, hon.
OMG... I shouldn't laugh, but... well, they were following your lead.
You dug in the dirt,
left something behind, and
then covered it up.
I sorry for your poor plants, though. What a way to go!
I do think there's a home-made spray to keep them out in the future... some kind of garlic mixture if memory serves. I'll have to look it up & let you know.