4 years ago I planted 2 sweet cherry trees in Guelph. They probably dont get as much sunlight as they should. All was well (I had some black aphids but having using a dormant spray) until this year when the leaves of one (see picture) yellowed and dyed. I can’t see any infestation. The other is fine. Any ideas? What should I do?
Hi – unfortunately your tree does look to be under some stress, but are you sure that it is completely dead? First check the twigs to see if your tree is still alive. Take a twig from your tree. If it snaps off easily, that branch is dead or weak; if it’s pliable and takes some effort to pull off, your tree is still alive. If the inside of the twig is brown and dry, that branch is dead or dying and may show that the rest of the tree is dead or dying. You can use your fingernail to scratch away the bark, as well, and see whether the inside is brown or green.
You may have to use a process of elimination to figure out what is going on with your tree. First I would make sure that there is no infestation present. As if there is, your other healthy tree may be at risk. Carefully examine the leaves; Leaf spot appears on leaves as brown or gray spots and is caused by a fungus that attacks the leaf tissue. The leaves eventually turn yellow and die. Dark spots on leaves that turn into holes may indicate canker. If this is the case you will have to immediately remove infected branches, or leaves, to make sure your healthy tree is not infected.
Borers are another common infestation, they may be easy to miss as they bore small holes in the trunk from which sap oozes. Small holes may appear in the trunk from which sap oozes. During the growing season some of the leaves and branches may wilt and die, turning brown. The holes made by the borer interfere with the tree’s ability to absorb water and nutrients so it is important to it is important to keep trees healthy by providing amble water and fertilizer.
A likely suspect might be scale. Scale bugs often do not look like insects at all. They may appear as tiny discolored bumps or blisters on the surface of the plant. Many scale bugs can be found along the branches of the tree. They may be relatively inconspicuous, but they like the borer, scrape away the bark of the tree and feed on the tree’s sap. Scale has been a big problem on other species of Cherry trees (Prunus) in Toronto this season.
If you are sure that it is not caused by an infestation, you may have to look at environmental causes for your unhealthy tree. By looking at your photo you tree looks to be getting enough sunlight but you might consider that its location next to the road may mean that your tree has suffered salt damage, cherries are usually salt tolerant but with the very icy and snowy winter we have just had, there may have been more salt than your cherry could handle.
You may wish to consult with an arborist to get a professional opinion with regard to the next best steps, Landscape Ontario’s website can help you find an arborist in your area.