I think it is highly unlikely your magnolia leaves are being eaten by slugs - much too tough for them... much more likely to be the dreaded vine weevil. Look for small black beetles and make sure their grubs are not chomping on your magnolias roots.

Thank you for your reply. I thought they were slugs or snails as there is a slimy trail deposit around the base of the tree. I have read that i need to go out in the dark with a torch to see if i can see adult vine weevils on the tree and destroy them.
thanks again x

Vine weevils eat out a very characteristic shape of hole, not really like slug damage, more like leaf cutting bees but with irregular edges. Try putting in vine weevil damage on Google Images and compare the shape.

thank you for your reply. i checked on Google images and they do not have the vine weevil characteristic hole on the leaves. they have left the leaves in a skeleton like pattern so this is why I think they are slugs or snails. i have purchased some grit that goes at the base of the plant to try and deter them. If not I have read that I can purchase a copper tape that will help?

Yes copper tape around the container, not the tree, will help if it is slugs. Also have you got the containers raised up off the ground so that nothing can get in from the bottom?

When you put the copper tape round the pot remember there might be slugs in the pot already even though no more will climb in. But if your leaves are being skeletonised (horrible word) two other possibilities are slugworms and leaf miners, though I don't know if either attack magnolias. It might be worth spraying with a contact insecticide just in case its slugworm. Don't know what to do about leaf miners but am sure somebody else will.

Thank you, I will try your suggestions, x x

Ihad a very young magnolia stellata which at 3 years was just producing it's first flowers. It was likked by slugs (of which I have many). Every leaf was eaten and now it has died. Any suggestions for getting rid of slugs.

Hi Doreen and welcome to GoY. Are you absolutely sure it was slugs that ate the leaves and not something else? Is you Magnolia in the ground or in a container? If the later it is far more likely to be vine weevil eating the leaves than slugs, but the best way for you to find out is to check after dark.