By Steragram2
Powys,
United Kingdom 
Water lily leaf beetles
The leaves of both plants are extensively damaged and not a pretty sight. There are holes everywhere, round the edges and in the middle. If damage continues at this rate I can't see how the plants will survive and I believe there is nothing to do but wait and hope for the best. Has anyone got a better idea please?
2 Jun, 2020
Answers
Thank you Eileen. Yes I can see the culprits (they are very small and numerous) I might e able to reach a few leaves but not most of them. Can't think wiping those few will make much difference and I might overbalance but nothing venture nothing win...Thank you for the link - I'll have a look.
2 Jun, 2020
Looked st the RHS site - the pic matches chironomid midge damage but I can see very small beetles. In either case there doesn't seem to be a lot to be done about it. the damage is very unsightly. Wonder if it will affect flowering - no sign yet.
2 Jun, 2020
This is the RHS link
https://www.rhs.org.uk/advice/profile?pid=827
as you say no chemical control. Can you see the culprits?
are you able to reach the plants and wipe the leaves etc?
2 Jun, 2020