Why are the leaves on our pear...

It sounds as though your pear tree has fire blight, a bacterial disease that makes the leaves look as though they have been burned and causes shoots to curl like a shepherd’s crook. Fire blight may also cause cankers to appear on the stems of host plants. The bacteria can be spread from one tree to another via insects, so it is necessary to treat the infected plant. Prune any infected parts about one foot below cankers, and disinfect tool after each cut. In addition, try spraying copper sulfate on the bud openings when the tree is dormant. If you plan to plan more pear trees, keep in mind that there are some varieites that are resistant to fire blight.