Bacterial Leaf Scorch
The symptoms of bacterial leaf scorch have been showing up in area trees over the last month or so throughout the county. BLS is an infectious chronic disease that is spread by leaf-feeding insects, such as leafhoppers and treehoppers. It attacks the trees' water transport system, which disrupts water transport to the leaves, stems and roots of trees.
Diseased trees will produce healthy-looking leaves at the start of the growing season but the margins of leaves will turn brown as the season progresses in late July and August. The brown area will be separated from the green growth on the leaf by a yellow or red band often called a halo on the leaf. Unless treated, BLS will cause the slow decline and death of the tree over two or more growing seasons. BLS is not a new disease, but it has become more common in recent times.
There is no preventive treatment, but you can manage the disease by pruning infected branches, using antibiotic treatments in the tree, controlling insect vectors, reducing water stress on trees by watering in dry periods and fertilizing to increase the roots and leaves. Many of these methods are not practical in forest applications but might be feasible if you have a large tree in your landscape.
It is best to consult with a certified arborist if you have specific questions. BLS generally infects oaks in the red oak family, sycamore, flowering dogwood and red maple.
Article by FCFCDB
Nature Notes for 9/30/2012