Re; Oriental lilies, What to do, I will be away for 3 wks. & am concerned about the horrid lily beetle?

Is there anything I can put on them now to help stop these 'nasty beetles', they, the lillies have grown so quickly & tall but I have noticed the horrors have had a munch from the top leaves. Obviously from when they started to grow. My friend who will be watering my garden is a diamond BUT is 'clueless' as to be rid of the beetle ie. to check every AM/PM & squash them. I would come back to just their stems, as they have a hard shell for a littlen! My friend has seen these comments about himself.& has agreed. love him, good to know friends are willing to help out these days??