When cutting diseased tree, shrub and plant branches and flowers do not put them in your compost bin.
If you do put diseased foliage in your compost bin all your compost will become infected with the disease.
To stop snails getting at your vegetables you can use crushed egg shells spread around the plant. It appears that the snails do not like to travel over the sharp and rough area that the crushed egg shells are on.
Another way you can stop snails etc. getting at your plants is to use crumpled up tin foil around the trunk of the plant or spread in a circle around the base of the plant.
Another idea is you can put a steep trench around your vegetable garden and the snails don't like traveling down the trench to get to the other side. I have tried this and it does work.