Knowledgebase

Bartlett pears deformed #279063

Asked September 18, 2015, 9:34 AM EDT

I pears every year are very deformed and useless,can you help me fix the problem? Phil

Midland County Michigan

Expert Response

Two possible causes--

1) insect damage such as caused by a stink bug early in the season.

2) Bartlett pear is susceptible to stony pit virus.

Here's an information sheet about stony pit:
http://pnwhandbooks.org/plantdisease/node/3668/print

The key feature of stony pit is that the affected areas (groups of stony cells) inside the fruit will be very hard, almost too hard to cut with a knife.  Note: stony pit refers to stony hollows, and does not refer to the seeds of the fruit. 

With insect damage, the affected tissue will be spongy, not hard and stony.  Also with insect damage, if you have nearby apples, you should see some of the same type of damage.  Stony pit will not affect apples.

There is no cure for stony pit.   Some years the symptoms will be bad, some years less.   

If you determine that it is probably insect damage, not stony pit, then increase your insect management sprays in the first 6 weeks after petal fall.
An Ask Extension Expert Replied September 18, 2015, 11:16 AM EDT
Hi expert,this problem has been persistant to the point pears are not useable, what do I do,cut down the tree as it is for sure stoney pit? Phil
The Question Asker Replied September 18, 2015, 2:15 PM EDT
I should have said that it is less common to see this virus cause symptoms in Bartlett, but it is not impossible. Seeing symptoms on Anjou and especially Bosc is more common.  

Is it possible you have a different variety?  The reason I ask is that Bartlett ripened here in SW Michigan over a month ago.  Those that weren't picked are mushy.

Be sure you are seeing the hard stony tissue in order to be certain you have stony pit.  See the attached file for picture of pears with leafroller damage.  With leafroller you can see scabbed over areas of skin where the larvae damaged the fruit when it was very small.  

Yes, we have no treatment for stony pit.  Once a tree is infected, it has it for life. It is a disease that is spread by grafting and by roots of adjacent pear trees growing together.  So if you decide to plant another pear tree, plant the new one some distance away or pull the old ones out first.

An Ask Extension Expert Replied September 18, 2015, 2:40 PM EDT
I guess I need a new tree. A friend has a tree with smaller pears hanging like grapes,tons of fruit and he calls them winter pears,he has no idea what they are but right they are hard as a rock. Any suggestions on what they might be?
The Question Asker Replied September 18, 2015, 2:54 PM EDT
Winter pears is a generic term for pears that need refrigeration for the best ripening.

Most common winter pears in this area are Bosc and D'Anjou.  You may wish to consider Harrow Sweet, a variety ripens two weeks after Bartlett and has extremely good fire blight resistance, excellent fruit quality, and very good storage life for an early pear. 

You will need a pollinator pear variety partner in the vicinity. It needs to be a compatible variety that blooms at the same time.
An Ask Extension Expert Replied September 18, 2015, 3:46 PM EDT

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