Winesap apple tree issues

(Question)

Hello, I live in Oshawa, ON. We have good quality top soil here, with mulch on top, and the tree is planted in a backyard with partial shade (sun about 1/2 the day). Tree is watered frequently in the evening.

I planted the tree two years ago, and both springs since have followed the same pattern: Tree has lots of leaf buds, leaves grow well, tree looks good. Then, around this time of year (late spring-early summer), all the leaves suddenly wilt and dry up. They stay green and stay on the tree for a long while, but if you touch them, they are brittle and crunchy and break apart easily.
What could be the cause? There doesn’t seem to be any insect infestation, no caterpillars, and I haven’t seen any mold. We haven’t had any low temperatures this spring either, so frost isn’t a worry.
Is there anything I can do to save my tree?
Thank you!

 

(Answer)

Thank you for contacting Toronto Master Gardeners with your concern about the health of your apple tree.

Without a photograph of the leaves, fruit or bark it is difficult to say 100% what is the cause of your ailing apple tree. From my research https://www.extension.purdue.edu/extmedia/BP/BP-132-W.pdf  I did determine that this particular cultivar of apple is very susceptible to apple scab and is susceptible to fire blight.

Apple scab is a fungal disease caused by the fungus Venturia inaequalis. Apple scab begins with olive green spots that turn black, and mid-summer leaves turn yellow and drop off.  The fungus overwinters in infected leaves, dead bark or fruit on the ground.  The spores from the fungus then start developing in late winter or early spring, and are released into the air by rain, wind or insects.  It then germinates on the new leaves when their surface is wet/humid and begins creating the spots.  Heavy infections cause the leaves to turn yellow and drop off . Take a look this is Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) article on apple scab to determine if your tree is in fact infected with this disease. One of our previous post titled Apple Scab on my Flowering Crab Tree? gives integrated pest management strategies.

It could be that your tree is suffering from fire blight caused by the bacterium Erwinia amylovora. Fire blight can infect all parts of a tree, not just leaves and fruits. 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. You did not mention if the infected branches curl down. Take a look this is Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) article on fire blight to determine if your tree is in fact infected with this disease. The University of Minnesota and California IPM  provide excellent detail on identification, cultural practices and controls. 

Good Luck