If the leaves of your rose plant are suddenly riddled with holes it is quite likely that the culprit is rose slugs. These are little slugs that can go through a rose plant in a matter of days. You will know they are the ones because they only eat the fleshy part of the leaf and leave the veins intact. There are no chemicals that come recommended, but there are some home remedies that have been known to work.
Yes, the best is beer. Leave a small dish full of beer in the garden overnight. The slugs will be attracted to the smell, crawl in and die. Empty the bowl into the toilet in the morning and keep doing this until there are no more slugs.
Another good way to make sure that they dont even come into your garden in the first place is to salt the perimeter. Slugs hare salt and they literally melt in it. As soon as they sense it they will simply turn around and go away. You can use kitchen salt but you are better off using Epsom salts as they contain magnesium that helps your roses thrive.
You can also get a spray can and fill it with vinegar it has the same effect as the salt. It stings the roses until they die. Make sure to cover all leaves. Do this just before nighttime sets in because that is when slugs come out.
Slugs like to follow the trails of other slugs so when you find a trail make sure to get rid of it right away. Rub it away using the tip of your shoes and salt it over.
If your roses are planted in pots and you find slugs on them the solution is simple coat the pots with Vaseline the slugs will slip and fall each time they try to get in.
These tips should help you get rid of slugs in roses.