Sticky Film From Black Walnut Tree

Question

We have a large black walnut tree in the middle of our backyard. This is our third year in this home. This is the first year that the tree is producing a sticky film. The film is all over everything on our deck and everything in our backyard. We can see the sticky film on the leaves of the tree. We have to wash everything down daily. The sticky film has killed all of the plants and flowers that were in pots on our deck and the hostas that were around the base of the tree. It seems to have killed a very large area of grass in our yard also. We had a lot of snow this past winter. We have also had some very hot and humid weather this spring and into our summer. We are wondering what is causing this to happen this year and is there anything we can do about it? We have young grandchildren who play in the backyard. The kids also bring their dogs when they visit. We are also wondering if the sticky film can make the children or dogs sick?

Answer 1

The sticky film is probably honeydew, which is produced by insects such as aphids and scale. Take a good look at the underside of leaves and stems for these creatures. It will take some persistence to get rid of it, if it is all over the whole tree. You may need to have a professional spray the tree for you. Here is more:

https://www.entm.purdue.edu/forest/pdf/16.pdf

https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-aphids-and-ants.htm

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