Question
I have a fruitless Mulberry Tree in my front yard in Northern CA, Santa Clara.  The tree has to be close to 30 years old.  I have never had any problems with disease or insects.  There is no cankers or sap seepage.  The problem, which just showed up, is the leaves are curling especially at the top of the tree.  They are no longer dark green but a faded light green.  I see no bugs or bites.  I water the lawn three times per week for 8 mins and stop watering from the end of November until the middle of Feb.  The tree has been pruned by the city three times in the last three years in the early Spring.  I have never seen it in shock or show any damage.  It also seems like the leaves that are curled are sort of bumpy, like blisters but no holes.  Not all of the tree is affected yet but at least 50% is. Tjere are no crispy or brown leaves. I see no weakness in the trunk.  I have no clue as to what it is or what to do.  I treated it with Copprspray one week ago.  The only different thing done this year that is not supposed to have an affect is the application of Spectracide weed and crabgrass killer.  I used a hose end application but did not spray near the tree base.  The crab grass is on one end of the lawn and spraying it would only affect the longer roots.  Can you recognize what the problem is from my description?  Please help.  This tree is the only form of shade I have to keep some cool in the house.

Answer
I would check the top leaves for aphids.  These insects infest many trees and cause the type of symptom you describe.  They wont kill the tree but can make the leaves defoliate prematurely.  If you find any bugs on the upper leaves, 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.  Let me know if you find no bugs.  Good Luck.