Look for info about codling moth.

Yes, the Codling Moth. Bane of the Northwest apple or pear grower. Although many pears are still quite edible after the bug's exit, still, it's not a pretty picture. I don't find any mis-shaping associated with this insect. Distorted fruits can be caused by severe Pear Scab which shows itself as black spots on the fruits' skin.

I'm still not sure that it is scab. The spots are softer, brown, not hard. Here is a picture of a pear, plus another one that is cut. There is no evidence of insect infestation. Does this help id the problem?

Here is a link that might be useful: {{gwi:1089941}}

Not scab. If it were, should be crusty.

Why did you say "but the core shows a bug has been inside."? I don't see any such evidence.

Thanks for the reply. Some of them have bug eggs and tunnels in the core, but not all of them. The one pictured had no bug residue. They sure taste good though!

Best to take your fruit to the Agri Provincial agent, or at least post a photo online for better identification of pathoogen.

Unlikely to be a pathogen. More likely to be a developmental glitch. Perhaps a nibbling caterpillar early in the season.

Again, it is best to take a sample to the Agri. Extension Agent for your Province, and have the Specialist look at the fruit directly. To 'guess' at your problem with no visuals, and such sketchy data, would give you pretty much a shotgun answer, that may hit the target, but probably not.
The paradox of getting a diagnosis of your problem, is, that the more qualified and trained the specialist, the more cautious the conclusions, since as time will prove, there are a myriad of problems that can affect fruit, and some problems mimic others externally.
Without even a picture of this pear, it is just a guessing game.

I appreciate your responses. There is a picture of two of the pears in a previous post -- one from the outside, the other showing the inside and core. The tree that is producing these pears is very old -- certainly more than 60. I think that it is likely a development issue -- we had such hot weather shortly after the pears started to form and it didn't get any watering during our long, hot, dry summer. I will drop in to our district agriculturalist and ask there though -- an idea I hadn't thought of.

Boron deficiency can cause misshapen fruit, and early scab infection can do so. there can be several problems working at the same time, so it is not wise to seek one only solution for a problem like this.
I would suggest getting a good soils test.
the knowledge would help you get a base line for all your gardening efforts.

Here's info and image of boron deficiency.

http://postharvest.tfrec.wsu.edu/marketdiseases/pearboron.html

Doubt that's OP's problem because it doesn't come close to a match of her fruit in the post (above) on Sep 8, 09 at 20:54.

Here is a link that might be useful: info re boron deficiency in pears