for things like the slugs and snails, if you put strips of copper or zinc around your bench legs it will repel them. I just read that zinc strips are more commonly found, but if you can find copper or zinc mesh screening, it will do the same thing as long as the strips are wide enough so that the bug would have to put all of themselves onto the strip before they could get across
edit - is that copper is more effective, but that zinc works
edit again - right after I typed this I followed another link, and someone was mentioning about how they were visiting a hosta garden where they had copper strips around all of the bench legs, and they saw a slug crawling right across the strip, and the hosta beds/leaves looked like swiss cheese.
so, i've heard this lots before, but it looks like your mileage could vary
edit - is that copper is more effective, but that zinc works
edit again - right after I typed this I followed another link, and someone was mentioning about how they were visiting a hosta garden where they had copper strips around all of the bench legs, and they saw a slug crawling right across the strip, and the hosta beds/leaves looked like swiss cheese.
so, i've heard this lots before, but it looks like your mileage could vary