Question
I have 3 azalea bushes in a bed with impatiens. The impatiens are very healthy and growing well. However, the azaleas seem to be bleaching out. New growth of leaves is a deeper green but established leaves are a very light, almost white green. What could be causing this?

I also have, in a different bed, lilac bushes that have black spots on their leaves. Is this an indication of a fungal problem?

Answer
The plants have had an infestation of lace bugs or spider mites.  These insects feed on the undersides of leaves.  If you will turn the leaves over you will most likely see some black residue left behind by the bugs.  The best treatment is with a systemic insecticide.  I would treat the plant with Bayer Advanced Tree and Shrub Insecticide.  This product is mixed with water and poured on the soil around the base of the plant.  It is taken up systemically and will kill the bugs within a week or so.  It also provides protection from reinfestation for up to a year.  You may want to wait and begin this process next spring as the new growth just begins to come out.  This should fix the problem quite nicely.  Good Luck.