Cliff Pfleider, Moorestown Department of Public Works, points out leaves on individual oak branches that synchronously show BLS symptoms. Even though some leaves do fall following death, many leaves remain until autumn. Young, small-diameter oaks may only live up to four years following onset of BLS infection. Older large trees, however, may survive up to 10 years and typically have numerous dead branches in their canopy. Dieback occurs when terminal ends of branches die progressively inward each year.
Trees become unsightly and possibly hazardous, necessitating their removal.
A mature oak infected over several years with BLS showing numerous dead branches. Injecting diseased trees with antibiotics reduces symptom development but cannot eliminate the pathogen, and injections are expensive and must be repeated. Tree life, however, may be extended by improving general tree health. It is recommended that soils where young, smaller-diameter oaks are growing be tested for pH and nutrients and amended accordingly. Irrigation and pruning needs also should be monitored regularly.