Hi: have several mature eastern cedars that are browning, they have small holes 1 mm diameter and there are some spots with dried sap running down the bark.
one tree was cut down last year, and i think the pests are spreading to these other tress, they are touching each other. this is a pic of some of the holes. The trees are in Toronto, Canada.
Any idea what the cause is? is there a treatment ? do you need more details.
thanx in advance
Ray in Toronto