Aren’t these little creatures lovely, the slugs and snails hold parties in my garden every night I’m tempted to put little signs up “no gate crashers allowed” they wreak havoc.
How to stop them! I think this has been the conundrum of gardeners for many years, Provado is a good guard against Lily beetle but if you don’t like to use chemical sprays I have heard you can use a garlic spray and found the following recipe.
Boil two pints of water, crush two large garlic bulbs "I would use cling film or a plastic bag to keep it all in place", crush using a rolling pin, add the contents to the boiling water to blanch for around 3 minutes, take off the heat and leave to cool, I would leave outside to cool garlic does have a strong odour. When cold strain the liquid into a jar to remove the debris through muslin or old tights, you could make more than you need and freeze some to prevent it going off.
This is your concentrated spray add one tablespoon to around a gallon of water you could add a little washing up liquid to help it stick to the leaves, spray all over the leaves and stems not forgetting the underneath every couple of weeks, you may find it better to spry late afternoon or evening after the sun has gone. The slugs will not like the taste and should leave your plants alone, especially Hostas with there big juicy leaves.
It's also a good guard against aphids I think it may be a good idea to test it on your plants first; if there is no sign of harm then continue to use, otherwise dilute a little more and try again. I think a little care should be taken as it could deter the predators of the pests you are trying to eradicate. Still kill any lily beetle you find and continue to remove the grubs until you can see the signs that the spray is working. You can buy a commercial garlic spray at garden centres, homemade is much cheaper.