As the leaves unfurl, I always take a good look to be sure. I examine the stems thoroughly. Leaves should be slightly crinkly and the stems should be grey with lighter lenticels.
This spring two branches are showing signs of disease. It's easy to detect. Lack of leaves, dry and flaking bark tissue and the loss of the smooth grey bark are tell-tale signs the plant has Eastern Filbert Blight.
The pathogen, Anisogramma anomala has invaded lenticels on some of the bottom stems, as shown here. I cut them off and brought them to a less distracted background for ID.
The pathogen splashes on to leaves and young stems, in this case enveloping the lenticels (stem breathing pores) and causing cankers. These cankers can appear 12-16 months after the initial infection. The cankers swell and expand, splitting the bark tissue, causing die-back and eventual stem decay.
The lenticels will darken with the bacterium and will become quite woody - hard.
I remember having a colleague tell me these were Scale Insects. From afar, they may look that way, but with this close up, you can see it's a canker for sure!
TREATEMENT: Cut back infected branches or to healthy growth with no evidence of cankers; to the main stem during dry conditions. Destroy or put in garbage. DO NOT COMPOST THESE INFECTED STEMS. Disinfect pruning tools after each cut. Prevent over-head irrigation/watering, especially any splashing throughout the spring/summer. Keep your eye on the plant throughout the summer months and prune away any stems where lenticels are becoming distorted.
With our situation, we are going to have a tough go - with the pond so close. Fingers crossed.
It's a common disease within Nursery Greenhouse Growing conditions. Can wipe out an entire plant if it's not nipped in the 'bud'.
Hint: One of the things I look out for when purchasing any Filbert (Corylus sp.) plant at the Garden Centre/Nursery. If you see these cankers, if so - look elsewhere. It's too bad this one now has it.
