Not fireblight - fireblight looks like someone has taken a blow torch to the plant, primarily at the ends of individual branches. And it would show up as more than just a single leaf.

Yours looks a lot more like scab. The best way to get an accurate diagnosis and recommended treatment options is to take samples in to your county extension office. Both the suspected disease and insect issues (although insects on foliage seldom pose much of a threat - usually more cosmetic than anything else).

Not scab either.

If only a few leaves are affected, ignore them, or if their presence bothers you,remove them.