Question
My Dad has a wonderful tea rose ,and I noticed that the leaves have, what appears to be, silvery looking 'spots' on some of them.  Some of the older 'spots'  look like holes. Insect or fungi? What can be done?

Answer
Young rose slugs can turn rose leaves to skeletons. They eat under the leaf which leave a clear layer of silvery tissue that eventually turns brown, dies and falls off. This is what causes the holes.  Older larvae are larger and are able to chew on leaves, taking bites out of them, as a caterpillar does. Any rose insecticide spray for chewing insects will solve the problem. Spray all around the base of the rose bush too because that is where they hide when not eating.