Bumpy pears from Stony Pit

Q. My pears were hard last year and really bumpy. We couldn’t even eat them. What can I do to fix this for my 2016 crop?

Gail from Negley

A. You have a viral disease in your trees. This is Pear Stony Pit, a serious disease of pear trees – but not their cousins, apples, in the pome fruit family. Bartlett pears will get this disease, but not show any symptoms. It is common in the Pacific Northwest, but uncommon here in the Midwest.

The symptoms first appear to be spots on the flesh of young pear fruits. As the growing season progresses, these spots appear to be insect bites into the pears that are sunken. That is because the stone is located in that area.

As the pear grows, the stone areas become even deeper pits in the skin of the pear, many times with a brown spot in the center.

Researchers say that if you try to cut into these stones, you will only push the stone deeper into the pear.

Sometimes, you may notice a similar issue on pears and apples that is not Stony Pit. It could be an insect issue.

We have yet to see brown marmorated stink bug damage on apples and pears in our area. We used lures to trap BMSB at one local farm after seeing what we thought were symptoms. The traps did not show any significant presence of BMSB in the orchard.

Sometimes, Stony Pit makes pears gritty internally, without having any larger “stones” in them. These pears are safe to eat. The grower should know this and look to control the disease in the planting.

The virus that causes Stony Pit Disease has not been isolated. The virus is mostly transmitted by grafting. Thus, Gail may have a tree that was grafted and the disease is already in the tree.

Sometimes, symptoms may not appear until the end of the second season of pear production. When the disease appears, the only control options seem to be selecting virus-free trees and removal of severely infected trees.

Research shows that the most severely infected cultivars include Bosc, Comice and Seckel. Other cultivars show signs, but not as prevalent or noticeable.

To read more about this destructive disease, go to http://go.osu.edu/stonypear.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Call the office hotline at 330-533-5538 to submit your questions. Regular clinic hours are over for the growing season, but you can still call and submit questions. Hours vary throughout the winter season.