Howard County Cherry Tree Premature Leaf Drop - brown edge holes in leaves
I was directed to ask here for recommended fungicide treatment for my ornamental cherry tree. The tree was planted as a root ball sapling 5' tall in the spring of 2001 then sodded around. Until 2009 there was no early leaf drop. In the spring the leaves come out full and healthy looking. About one week ago, the brown spots started to show up on some leaves, progressing to small holes about 3-5 mm in diameter. Affected leaves dry up like in fall colors and start to fall in July. By September the tree is almost bare. Another cherry in my yard died and was removed last year. All of its roots were rotted. Pictures attached. I use fertilizer with weed killer once every three or four years, or hand pull. I usually use Scott's Number 2.
Added tree trunk image to show ground around base. The mulch is not coned up around the trunk. It is pulled back to the earth trunk margin.
Howard County Maryland
Cherry trees are prone to several fungal leaf spot disease. A common one is cherry shot hole. The fungus kills spots on the leaves and the dead material falls out of the leaf leaving a hole. Leaves yellow and fall. Defoliation is not unusual. It is highly weather related and may not happen for years and then occur for several years in a row.
You want to minimize infected plant material that reinfects the tree by raking up fallen leaves and disposing of them off-site. As long as defoliation does not occur year after year, trees should be okay. Most homeowners either tolerate the occasional defoliation or remove the tree.
It is hard to control this with fungicides. You can spray just when the leaves are starting to unfurl and at 2 week intervals thereafter. Daconil or Cleary's are two fungicides you can use, though others are fine, too. Do not spray when pollinators are visiting blooms as fungicides can be harmful to them.
It's good that the mulch is not piled on the trunk (like a mulch volcano), however we recommend that the mulch not actually touch the trunk. You should be able to see the flare of the trunk, i.e. where it widens as it goes into the soil.
The tree with rotted roots is a completely different matter, and it is impossible once a tree is dead to determine for certain what killed it.