Gray mold is a relatively firm decay, and fruit has a spongy but dry feel when squeezed.
It is generally recognized that the origin of the spores that cause gray mold is in the orchard, but the exact timing of when the spores germinate and infect the fruit in north central Washington is still under investigation. When the decay encompasses the entire fruit, the fruit looks like those in A and B above. Recent studies have shown that Botrytis cinerea can be isolated from pear stems and calyxes before harvest, and that spores can also be found on the outside of the fruit while in the orchard. There are several fungicides that are effective against gray mold, including Ziram, Captan, and Mertect. Alternaria rot of 'Bosc' pear, caused by Alternaria spp.