Morello cherry tree is dying at the tips of branches and has a gingerly grunge on it. Is this treatable and, if so, with what?
Morello Cherry Tree Is Dying Off
Certified GKH Gardening Expert
What does this 'grunge' look like exactly? Soot like? Rust colored? Sticky sap? It could be insect pests affecting your tree, possibly borers or a sap-sucking insect. If you are noticing any black sooty looking stuff on the tree, this would definitely be insects (aphids, mites, etc.) and the sooty mold fungus comes from the honeydew these insects secrete. A sticky sap could also result from these pests as well as borers. I would examine the tree for signs of insects and treat with Neem oil, which is both and insecticide and fungicide. You may also want to prune away any affected/dead growth.