The search for a pear tree that would withstange fire blight.
In the early 1900’s, the economically important northwest pear industry was seriously threatened by the fungal disease fire blight. Researcher Frank Reimer found that Pyrus calleryana was a good species for trying to develop resistance or use as rootstock to overcome this problem. With only a few callery pear trees to work with, he persuaded USDA explorer Frank Meyer to visit China, home of that species, and collect seeds. Meyer and others made several trips to various areas where the Asian species grew and sent home copious amounts of genetically diverse seeds. Back in Oregon and in Belt Way, Maryland, researchers planted out these seeds to see which would help the pear industry to survive– and began grafting fruiting pears to the myriad Asian trees that quickly grew. And from that good deed, a dreadful invasive species got its start.