'Lost Pears'- not lost, just missing

17 years ago

This thread is in response to the "Fire" thread started by Klakos:

http://forums2.gardenweb.com/forums/load/fruit/msg031710015303.html

I contacted Corvalis to get clarification on what Dr. Postman meant by "Lost" in his communication with klakos

He told me that he didn't want people to think that pears at the genebank are being lost to fire blight. That is not the case! He indicated that he has often said that they are preserving "lost" pears, and he even wrote a paper about the "Lost Pears of New York" in an attempt to find cultivars that were illustrated in U.P. Hedrick's "The Pears of New York" but which are not in their germplasm collection.

He said that one of the reasons that Corvallis was selected as a location for the pear germplasm collection is because fire blight is rarely seen on pears in that area. The Erwinia amylovora bacteria is there, but they are more like to see the disease on apples than on pears. Apples are generally less susceptible to fire blight than pears, but they bloom later when temperatures have increased. When pears are in bloom there, the temperatures in western Oregon

are too cool for fire blight to develop (he indicated that the temperature threshold for fire blight is about 60 F). Instead, they are more likely to see Pseudomonas blight, which is caused by a different bacteria that enjoys cool damp weather. Pseudomonas is not as damaging as fire blight, however.

They have occasionally seen fire blight on pears and quince when overhead irrigation is used on young plantings during the summer, but he has never seen fire blight in our pear germplasm orchard. They use drip irrigation to avoid wetting the above ground parts of the plants during warm weather, and in Oregon the rain mostly falls in the winter when it is cool, and not in the summer like it does in most of the eastern U.S.

He said he believes that Corvallis is the perfect place for a pear genebank for that reason.

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