hemerocallis midge

Hi I am wondering if anyone has any tips as to how I can stop my Daylily's getting infested with the tiny maggots from the midge , I know it is the early daylily that gets it and not the late flowering one, but I love them and try to stop it but to no avail, I destroy the infested buds but they still get affected every year.

any tips please I thought if I smeared the tiny buds with vaseline that might help ?

regards Barbara