What's eating my apple tree?

[cjard]

I've a bit of a puzzle.. A while ago I saw several neglected fruit saplings in a local Aldi on offer because they'd wilted (hint to Aldi: try watering your plants in summer) so I bought them as a rescue project

Not having anywhere convenient to plant them at the time I've instead kept them in pots indoors. Tending to them at the weekend I saw one of them had been quite seriously chewed up by something, but I couldn't find any creatures on the sapling itself, just a lot of snail trails all over it. Ordinarily I would just write it off as snails, slugs or similar trail leaving specimens, but here's my puzzle:
These plants have lived for nearly a year inside an incredibly dusty, dry warehouse type building. It's definitely not the sort of place that a siding mollusc would entertain crossing just to get to a fruit tree. In addition to a dusty floor, it would have to scale the side of a bucket, a moat (effectively, I keep the planters in buckets with a small amount of water in the bottom) and then the side of the planter




Thanks!

[Jungle Jane]

Ive had slugs living in the bottom of some of my pots,but smaller pots,easier to turn upside down to have a look. Have you found any webbing on any leaves,like a cocoon has been there? Just checking it's not sawfly? The larvae are like tiny caterpillars & same colour as the leaf. Hope it's not them. When you plant the trees out,the slug will probably appear,don't plant it!