Bumps appearing on trunk of Silver Birch tree

Question From: 
Matt Jackson in  Point Cook,  Melbourne VIC


Nature of problem: 
Bumps appearing on the trunk of my Silver Birch tree


Type of Plant (if known): 
Silver Birch


Symptoms of Plant Illness (please try NOT to diagnose your problems yourself): 
Leaf drop, bumps on trunk starting from about 50cm from base going up the tree and onto branches


Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type: 
clay. Garden beds were mixed with sandy base soil and the existing soil type


How often do you water the plant:
The trees are only watered when it rains. I fertilise twice a year


How many hours of sunlight does the plant get each day:
8 hours. the tree is planted on the northern side of the property


What type of plant is it:
Silver Birch


How long since you planted it:


Have you fertilised? If so, with what and when:
I fertilise twice a year. Scotts “Osmocote Landscaping all purpose plus trace elements” or Scotts “trees, shrubs”


Is the plant indoors or outdoors: 


What other treatments have you given the plant: 

Upload photo if available: 

Other Comments: 
I hope all the photos have been uploaded. It only allowed me to browse I click on the photo not sure if it’s attached. I have 2 Silver birch trees side by side one has the bumps the other does not have bumps and looks a lot healthier than the with the bumps/pimple like bumps. The tree also has a resident distinct looking bug/beetle I’ve only seen one or two. I’ve included a photo of the bug.


Answer: Hi Matt,  That is a shield bug and like all bugs (eg cicadas), it sucks sap: it is probably doing little harm.  Silver Birches are really struggle in Sydney – in Melbourne where you live they do much better, but they still have some problems. Erratic behaviour where the odd one gets sick and eventually fades away are common. You are close to the bay – if your soils are very sandy, make sure that the radius of 3m around the Birch is well mulched. Both trees will need fertilising with a half dose of citrus food once a year. Trace elements are the key thing here. Watering at least once a week during dry periods is also essential.

Your sick tree has a seriously compromised immune system caused by less than ideal growing conditions, hence the (I guess) bacterial lumps.  I only got the one photo showing the shield bug and I did not see the lumps.  Don