Plant Diseases/forsythia


The tips of some of the branches of my forsythia bushes are turning brown. Perhaps as much as 12" down from the tip; some even more. I transplanted them about 6 years ago and they are now over 6' tall. This year, they were absolutely spectacular at blooming time. Most are located across the entire front of my lawn. Another 12' span are up closer to the house. Can you help me?

Hi Linda,

The two most likely causes of the problem are the plant pathogens Sclerotinia or Botryosphaeria .  For tip blight caused by Sclerotinia , you will want to look for several diagnostic features.  You may notice alternating light/dark pattern on the affected twigs and internally, there may be black structures called sclerotia within the stems.  If you go to this web address, there are several pictures that show you exactly what to look for.
If the problem is Sclerotinia, the best recommendation is to prune out and discard infected stems.  It may be helpful to treat with a fungicide.  The registration of fungicides varies by state but a few suggestions can be found at this link.

As for Botryosphaeria canker and dieback, the symptoms are not quite as clear.  Plants will exhibit the dieback you've described and you may be able to find staining of the internal wood.  However, it is not always obvious.  Eventually, fruiting structures would form on the affected branches which look like small broken areas and can be as small as grains of black pepper.  If you go to this web link, you can find information and pictures about this disease.

Good luck!

Plant Diseases

All Answers

Answers by Expert:

Ask Experts


Jennifer Olson


Plant diseases affecting vegetables, fruits, nuts, lawns, trees, shrubs and ornamental plants. I have just volunteered as an expert on this site as of 01/2011.


Identification and management of plant diseases. Have been employed as a Plant Disease Diagnostician since 2002 and currently work in the Plant Disease and Insect Diagnostic Laboratory at the Oklahoma State University.

National Plant Diagnostic Network, Great Plains Diagnostic Network

B.S. Biology - Lebanon Valley College; M.S. Plant and Soil Sciences,concentration Plant Pathology - University of Delaware; Ph.D. in progress - Oklahoma State University.

Past/Present Clients
Home gardeners, Hobbiests, Plant Breeders, Extension Educators, Nurseries, Greenhouses, Golf Courses, Departments of Agriculture, Industry professionals

©2017 All rights reserved.