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BLS has been very damaging to red oaks in Delaware and the Mid-Atlantic states since the early 1990’s

BACTERIAL LEAF SCORCH (BLS) of hardwood trees, shrubs, and herbaceous plants, is caused by the bacterium, Xylella fastidiosa, carried by small insects such as leaf hoppers and sharpshooters. BLS has been very damaging to red oaks in Delaware and the Mid-Atlantic states since the early 1990’s. Northern red oak and pin oaks under environmental stress are more susceptible. Symptoms include marginal discoloration or scorch of leaves in late summer or early fall, often with a yellow or dark band on the inside edge of the discolored area. Symptoms are similar to those caused by drought or root issues that interfere with flow of water and nutrients. Plants may not develop symptoms for a year or two after infection, but then thinning of branches occurs and trees die within 5 to 8 years.  Infection is confirmed with a lab test for a fee, so if confirmation is needed, please arrange to have samples tested by contacting the UDBLS Red Oak 2016 Plant Diagnostic Clinic. Please note that there is a $20 fee for BLS testing. To manage, maintain good tree vigor, and remove infected trees. A UD fact sheet has more info: http://extension.udel.edu/factsheets/bacterial-leaf-scorch/
NFG 8/30/2016

A new fact sheet from UD Cooperative Extension highlights information on bacterial leaf scorch (BLS) of oak and other trees.  BLS has been problematic in oaks in the red oak group for almost ten years, and has led to the decline and death of many oaks in Delaware.  http://extension.udel.edu/factsheets/bacterial-leaf-scorch/