Question
A while back the leaves on my rose bushes got white spots that looked like water spots.  Now the leaves all look lacey and full of holes.  I don't see any insects on the leaves. What could be causing this?

Answer
There is a small caterpillar that looks a lot like a tiny black slug, called a sawfly.  These insects suck out the juices from the undersides of the rose leaves. This means the top of the leaf stays green for a little white but because it hasn't any liquid in it, finally dies and the white area becomes a hole. Here is more information for you in regards to what they do and how to control them. Keep in mind that when you spray a rose for any insect, always make sure you spray the ground all around the base of the rose bush as that is where the insects go after they have done the damage on a plant, to pupate
http://www.finegardening.com/pages/g00171.asp