Thursday, May 6, 2010

Fireblight in Pears

Here is a Bartlett Pear tree, one of the most common pear trees in the United States. Unfortunately it is plagued with fireblight in many areas of the country. This is a prime example of where resistance breeding could come in very useful. We need to breed for horizontal resistance in pears. From my experience, the European pears are highly susceptible to fireblight. Most of the pears we planted in Idaho when I was young died within a year or two from fireblight, whereas the apples survived with no problems. It was only when we bought pear varieties from St. Lawrence Nurseries, a company that sells pear trees for locations where commercial pears will not grow, that we were successful at growing pears. When European settlers came over to America they planted pear trees from seeds. These trees grew very well, as pears put on more growth per year than apples without the need for much if any fertilizer. Excessive fertilizer may be part of the problem today in addition to a monoculture of Bartlett trees with low horizontal resistance to fireblight. When pears are planted on fertile soil or fertilized much at all, then they grow rapidly and seem to be more susceptible to fireblight. The early settlers used pears for pear juice or cider and they grew them from seeds. I suspect that these trees had much less problem with fireblight than the pear monoculture we have today. Apples later took over the place of pears, but do not have as fast growth as pears and as great an ability to grow on poor soil, almost, but not quite. I would highly suggest trying other varieties if you have fireblight in your area.

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