Fruit Trees

(Question)

I have a pear tree that seems to be afflicted with something. The soil generally has a clay base and the tree is in an open space that gets lots of seun. Wet and dry condition would be reflective of the actual climate conditions for this area (Sudbury). The climate zone I believe is either 2 or 3.
The pear tree has sections of the tree, probably about 70 %, that seem to be dying off prematurely to the leaves dropping. A similar situation happened last year but the tree seemed to come back this year with blossom and with fruit. I have included several pictures of the tree. The bark seems to be in good condition and this is a mature tree. I do fertilize it year with fruit tree spikes. I do have another pear tree in the garden that does not have this problem.

Any advise you can give will be greatly appreciated.

GEO_0410

(Answer)

Thank you for contacting Toronto Master Gardeners.

Only one of your pictures came through with your question. It is difficult to see but from this picture it looks like you may have Fire Blight. This is caused by a bacterium,  Erwinia amylovora, to which pear trees can be very susceptible.

When a tree has fire blight it effects new growth and causes the branches to die and the leaves to shrivel up. The end of the branch has a characteristic “shepherd’s crook” appearance so the end of the effected branches curl down. It is difficult to see if your branches are doing that in the picture.

If this is indeed what you have your main concern will be to protect the tree that is not infected at the moment as this is highly contagious. When cleaning up your infected tree good sanitation is important. Remove branches and bag the branches and remove them from the yard so the bacterium can not travel to the healthy tree. Make sure your tools are clean and sterilize them afterwards so you do not pass on the infection when you use your tools next.

Here is an excerpt from the Ontario Ministry of Agriculture on pruning the effected tree:

Ugly stub method of pruning

If an orchard becomes severely infected with fire blight, consider pruning out active blighted strikes using the ugly stub method. Cut out the strikes when symptoms first appear and before extensive necrosis develops. Make cuts 30 cm or more beyond the visible symptom in at least two-year-old wood or older, being careful not to cut back to the next healthy limb or spur. This will result in leaving at least a 13 cm naked or ugly stub. Paint the stub with a bright colour for easy identification in the dormant period. Avoid excessive cutting that stimulates the development of succulent growth and extends the susceptible period for shoot blight infection. A small canker may develop on the ugly stub but the tree usually confines the disease to the ugly stub. During the dormant period, prune all ugly stubs from the tree.

I have included links for you with the information from the Ontario Ministry of Agriculture and Agriculture Canada. On these sights they outline preventative techniques to help you try to keep your other trees infection free.

Good luck and I hope this information is helpful to you.

http://www.omafra.gov.on.ca/english/crops/facts/fireblight.htm