Question
I have several different plants that are exhibiting the same symptoms.  I have examined the plants for insects but have not found any.  Plants that are affected:  Shasta daisy, Russian sage, Lamb's ear, snapdragons, and several others.  The symptoms include small round browned spots on the foliage causing the leaves to curl and brown. The spots are not scaly and in some cases become holes or are clear.  The spots are small, close together and very numerous.  I had this problem last year but to a much lesser extent.  The plants affected are all in the same area of the garden bed.  The soil conditions are sandy loam that has been amended with compost and sphagnum moss. pH somewhat acidic. Light conditions are full sun from 9AM on.

Answer
Hi Linda,
Thanx for your question.  It sounds like spider mites.  You can control spider mites with insecticidal soaps or oils which are available at your local nursery.  Also, spraying the plants regularly with the garden hose will knock them off of the plants. If this doesn't work then it could be a rust or fungus which is harder to control but it sounds like spider mites to me.  Try the insecticidal soap and let me know what happens.  I hope this helps.
Tom