We think the damage pictured might be both -- overlapping symptoms of Fire Blight plus cold injury from late frosts. In recent days we've received several inquiries about trees with Fire Blight symptoms (crabapples, apples, pears, etc.). If you are preventatively spraying your fruit trees for the typical pests and diseases encountered in our area, as is recommended, then you are probably protecting them sufficiently from Fire Blight infection.

One way to distinguish between cold injury and infection is waiting to see if new growth appears after the damage manifests. If only cold-injured, branches with leaf damage will regrow; if infected, they will not, plus decline can continue as the bacterium moves further down the branch and deprives more growth of water and nutrient flow.

One of our tree/shrub reference books that includes Crabapple variety rankings does list 'Snowdrift' as ranging from having moderate to high or even severe susceptibility to Fire Blight. Other sources do mention a vulnerability to this disease for 'Snowdrift' but don't list how severe it might get.

It's hard to tell if the second Yoshino cherry you describe is dead or just weakened enough that it isn't ready to leaf back out yet. Plants tend to lose freeze/frost tolerance once they break dormancy, no matter how prematurely that dormancy might be broken due to a warm spell, so it's possible the sapwood in that young tree couldn't withstand the temperature drop. Frost pockets are places in the landscape that collect colder air (because it sinks down into low points between hills, for instance) and if one tree happens to be planted in one, if the ground isn't fairly level there, maybe that influenced its ability to tolerate the temperature swings.

Perhaps something unrelated to (but overlapping with) the frost damage is preventing it from recuperating. Is the plant surrounded by lawn, where maybe mowing or string-trimming damaged the bark on the trunk? (Such injuries can kill a tree.) Perhaps it had unhealthy roots or not enough roots when planted, since bare-root plants are more perishable than containerized plants since they can dry out easily prior to planting. Maybe it was over- or under-watered around the time of the frost, or roots were struggling and, without the support of carbohydrates from photosynthesizing foliage feeding new growth, couldn't replace any lost roots or establish new ones. Time will tell if the leafless cherry can recover, but if you don't see new growth fairly soon (by late May or early June, maybe, given your location in western MD), it might have been lost.

Miri

Good evening,

 

Thank you very much for your quick response to this question, and to my question about the scale insects on my young oak tree.

 

I will keep a close eye on the crabapples to see if it looks like any regrowth is starting to happen now that it looks like we will have a stretch of warm weather.  I have not seen any signs of fire blight on any of my other fruit trees, and I do have 6 apple trees and 2 pear trees, so they could be susceptible to it.  Also, the fruit trees are located in between the crabapples, so I would think if there is an infection spreading around it would have gotten at least one of the fruit trees.  The other thing is that all but two of the fruit trees have been in the ground for 2 years or more, so they are probably better able to deal with things than the crabapples that were just planted a year ago.

 

I have not started a spraying regimen for my fruit trees yet.  The oldest ones were planted in September 2020, and the most recent one was planted early this spring.  I have not had any disease problems so far, other than a little cedar apple rust last year.  I removed the infected red cedars from my property over the winter, and so far I haven’t seen any signs of it on my trees this year.  So, I guess I should look in to the spraying schedule to try to protect things a little better, just in case.

 

The two Yoshino cherry trees were just planted this spring.  They have trunk guards on them, and are surrounded by mulch beds about 24 inches in diameter, so they haven’t been damaged by a weed whacker or lawn mower.  I guess the more likely scenario for them is that one of them was just more healthy and/or had a healthier root system when it was planted and was better able to recover from the frost.

 

So, I’m watching all of those things closely, and keeping my fingers crossed that they will all recover.

 

Also, I removed all of the scale insects from the oak tree that I asked about in a separate question.  The tree is young and only about 5 feet tall, so it was easy to reach all of them and get them off.  The worst thing was that the tree is about 5 feet away from a nest box with tree swallows in it, and I was being dive-bombed by an angry bird the whole time I was removing the scale insects!

 

Thanks again,

Jason 

Hi Jason,

Fruit tree vulnerability to fire blight and other diseases varies from one cultivar to another, and may also depend on exactly when they were blooming (as the spores are through to primarily be introduced to the plant on pollinators visiting the open flowers). Therefore, it's conceivable that the crabapples got hit hard this year while other fruits nearby avoided infection. In this situation, how long the trees have been in the ground is likely not a factor, though it might impact other forms of tree stress susceptibility.

Our When to Spray Fruit Trees page provides illustrations and brief descriptions as to the types of certain stages of growth referenced in most spray schedules. These are used more so than calendar dates because weather variations will cause trees to break dormancy at slightly different times each year, which in turn impacts when pathogen spores will be on the move. Trees are vulnerable to different pathogen spore infection at different times, though overall these windows of time tend to overlap in spring, though might extend into early summer. Spraying manages pests too, so some of these will also be applied at specific times, which relates to the insect's life cycle and what life stage does the damage. Sometimes new fruit tree plantings escape significant pest/disease problems in their first few years if there aren't many fruits in the immediate area (so the insects or pathogens have to "find" the hosts) but eventually they tend to catch up. Be advised that while removing rust-infected junipers in the immediate vicinity of vulnerable fruits is prudent, spores of rust fungi can travel for a mile or more on the wind, so future reinfection is always possible.

Mulched zones around trees is great but just make sure that the mulch doesn't touch the trunk itself, leaving a bit of a void in the center so the bark is uncovered and continues to get good air circulation. (That is, don't use a "mulch volcano.") The mulch layer should be a flat three inches deep or less in order to not suffocate the roots.

Some birds do actually consume scale right off the branches, but we don't think Tree Swallows do since they prefer to catch insects in flight. Hopefully the parent birds weren't too perturbed afterwards. Good luck!

Miri

You're welcome!

You're welcome. Good luck! The lack of foliage on the cherry is not encouraging and while a scratch test can sometimes be unintentionally misleading and giving false hope regarding the potential for regrowth, all you can do is give them a bit longer (until the scratch test doesn't reveal any green tissues) if you want to be certain it's a lost cause. If keeping them isn't holding-up a process for replacing the trees, there's no harm in waiting a little more.

Miri