Brown Crab Apple Flowers

Hi Guys, I was wondering if you could help me.

I've got a Crab Apple that I've had for many years that has always been trouble free. I've just noticed that some of the developing flowers have turned brown and a couple of the leaves have got a couple of brown blothes. Any ideas what it could be?

The tree was re-potted earlier this year and was putting on excellent growth and all the flowers and foilage seemed fine up to and including Wednesday of this week. We have had alot of rain here in the South East in the last couple of days, could this be part of the problem?

You have blight symtoms on crabapple (pretty susceptible to fireblight, depending on cultivar) and on Pyracantha (which is slightly susceptible to fire blight). With rosaceous plants, one always has to worry about fire blight, so the best thing to do is to call Cooperative Extension and find out if you *have* fire blight in your area. Some places have a lot (especially places with lots of fruit orchards) and some places don't. Fire blight is a bacterium that is spread by rain and insects. If you have bees, you might expect to see the infection start with flowers. Go here:

http://www.donnan.com/fire-blight.htm

for a similar story. Go here:

http://www.extension.umn.edu/yardandgarden/ygbriefs/p223fireblight.html

to find out if your crabapple cultivar is especially susceptible.

I think you should take this very seriously. If you bring in a sample and your extension agent confirms that you have fire blight, you should prune off all infected leaves and branches from these trees. Note: Sterilize your pruning tool after EVERY CUT. Use 10% bleach or 70% ethanol, but do make sure to re-oil your tool after finishing or you'll ruin the tool. If twigs are infected, prune a few inches below the infection. Watch the tree carefully to make sure you caught all the infection.

After pruning off the infected tissue, you need to spray these plants with a protectant. Ask Cooperative Extension what to use, but a copper sulfate spray will be effective if you spray frequently to keep leaf tissue covered even as the tissue expands and new leaves emerge. You may have to do this every spring, or only during wet springs.

Let us know what you find out. If you're lucky, it's only frost damage!!

Hi Jim/Nina,
Herewith the front & back images of my poor Crab Apple.
It looks like your diagnosis was correct as the trees are getting worse on a daily basis.



I've taken your traement plan for my infected trees and will get some Copper Sulphate today to spray this evening/tomorrow morning.

Thanks again for all your help and I will keep you posted,
Regards,
Simon

I should have checked your location before giving you so much AMURRICAN information on fire blight, but a quick internet search assures me that the UK has fire blight. So: continue worrying.

I can give you an exciting project to do! Take a couple of those brown buds and put them in a plastic baggy on top of a piece of moist (not wet) paper towelling. Put in a warm dark spot in your house, and wait one or two days. Then you might discover the tissue covered with what look like dark metallic hairs that branch at the tips.

If this is what you see, the buds have been attacked by a fungus called botrytis. My peonies used to have their buds turn brown (heartbreakingly) every year from botrytis blight until I wised up and moved the bushes a foot away from the house, where the better air circulation fixed the problem.

This may not mean the tree is free from fire blight (botrytis comes in on tissue killed by other things), but because you have three different species of plants suffering from miscellaneous ick, it's possible your back shelf just has poor air circulation and everything back there is too moist. Then I could happily tell you to get those trees some fresh air.