Asiatic and Tree lillies round semi circle bites on leaves

Calla lily is not related to the real lily so I think it's very unlikely lily beetle would attack them.
You leave the foliage to build up the corms for next year.
I'm guessing you have the coloured ones and not the large white variety.

 

@pete
yes I have the coloured ones. Never had them before but choice was so limited in the shops this year I picked them up coz they were there and they vaguely went with my colour scheme. They have been a bit short lived for my liking. Not much bang for my buck

 

@ThePlantAssassin As Pete says Calla lilies are not related to real lilies they are members of the Araceae related to Arums and Arisaema. Remove the flower heads but let the foliage die down in it's own time. In my experience they are pretty much pest free.

 

They're using my bee home at the moment, put it up in March but they only started using it in June. They've sealed up three bamboo canes so far, another cane has some bits of leaf at the back of it.

Nick

 

Ah Ha My neighbour has just put several of the above bee homes up in her garden........I guess I now know where the Bees that are destroying my wisteria are coming from!

 

I think they are pretty particular about the size of the holes as well as the leaf type.
Although I get them tunneling into the cacti pots and lining the tunnels in the sandy compost, had some plants with pretty much no compost left under them, just tunnels and leaves.

 

Thank you. I thought i'd got rid off all those pesky things! I normally spot them because of there bright orange shells. Thanks