Pear Leaf Blister Mite
These tiny mites live within the foliage with several gernerations occuring during the summer. This problem is first recognised in the spring when the young foliage develops pink or pale green blothes and gradually turn brown/black. During the growing season the tree will exhibit a generally unhealthy appearance but this seems to have little effect on the trees overall vigour and does not effect the fruit. Not a major pest of pear trees.
There is currently no chemical registered for the control of this pest.