Fire Blight look alike in Carmen Cherry

Asked June 6, 2016, 10:59 AM EDT

My Carmen Cherry bush bloomed great this spring and set much fruit for the first time. Now the tips of many branches are drooping and some fruit and leaves are turning brown. This occurred over a very short time. The rest of the bush seems fine. Please see attached pictures.

Itasca County Minnesota

3 Responses

I have never seen anything like that on cherry. Is there any pattern? Only some branches and not others. Do you see any wounds or gumming below the wilting?

No apparent pattern. But mostly just new growing tips. Not wounds or gummy areas. Could it just be a stress response because the temps have been going up and down drastically or just a natural self pruning due to the abundant new growth and heavy fruit set? Thanks for any ideas.

I sent your pictures to several people and most were also stumped.
No I do not believe it is a stress response for cold then hot. Browning at the base of the stems and wilt of stems are a disease. One colleague suggested European Brown Rot (Monilinia laxa), This is an uncommon disease of cherries which infects the blossoms and kills them and the spurs that they are on. It does not usually kill new shoots.
Bacterial canker (Pseudomonas syringae) but again the symptoms are not right. But several people have suggested this as the most likely disease.
When I first looked at the pictures I thought it looked a lot like fire blight (but fire blight does not go to cherries). It showed several classic symptoms. The shepard's crook wilting of new shoots and the death of the base of the leaves as the infection moves into the leaf from the stem. I did a internet search on fire blight in cherries and found references to fire blight (Erwinia amylovora) on cherries.
Both Bacterial canker and fire blight are bacterial diseases. The infection took place during bloom and was probably accompanied with rain which washed the bacteria down into the base of the flowers where it entered the plant and began to kill plant tissues. The bacteria is now spreading in the plant. There are no treatments after infection. I recommend cutting out all the infected shoots 8 inches below where you see any sign of the the disease. Here are some links to more information. Most of the literature is on apples where it is a common and devastating disease but all the recommendations would be the same for cherries.
See the links at the bottom of the article.
You may want to contact the University of Minnesota's Diagnostic Plant Clinic to have them confirm the presence of a bacteria in the infected tissues or in the apparently healthy tissue adjacent to it..
Pruning out the infected tissues is probably worthwhile.
I attach a picture of fire blight in apples showing the same symptoms as in your photos.