Weeping mulberry tree

Question

My weeping willow, which is approximately 40 years old, has developed some brown sap looking places on the bark, plus it seems to be dripping the sap. Can you tell me what this could be and how do I stop it?

Pat VanBebber

• 

Answer 1

The most common cause of dripping willow trees is an insect infestation. Most likely, the dripping substance is actually honeydew, the waste of aphids and scale insects that consume sap. Both commonly infest willows. In this case, you will probably be able to see the insects themselves, though they are tiny:

https://www.gardeningknowhow.com/plant-problems/pests/insects/aphids-tree-disease.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/control-plant-scale.htm