I have slipped a long way back and can feel the pressure of a blogging backlog so I best bite the bullet and post these photos. 

A while ago I noticed reddish stains appearing on the tops of my pear leaves or at least one reddish stain on one pear leaf.

I humphed and pfftted a bit, but did nothing further. When my folks visited last weekend I sent them off to investigate and it seems that almost every leaf is now troubled and the underside has a peculiar spikey growth, reminiscent of an Ankylosaurus.

We picked it apart but didn’t find evidence of any juicy bugs.

Anyone know what it is?