Forsthia damage. Root damage or fungus?

Asked May 10, 2015, 9:02 AM EDT

Immediatly after flowering several branches of a bank of forsythia wilted. The bushes are 20 years old or so. I purchased three bushes last year from home depot, which seemed to be hit first. I'm wondering if the damage is from winter or a blight. Also, as the bushes are next to a bush that the deer browse I am reluctant to trim the dead branches at this time due to tic season. Can I avoid trimming now if is a fungus? Regards, Joe

Frederick County Maryland

3 Responses

From your photos it looks like the forsythia were subject to sclerotinia, a stem blight. Black nodules of fungal tissue are found inside the stems when split open. To control we recommend pruning. Prune infected branches before the dead tissue falls on the ground and gets into the soil. The fungus can overwinter. Thin the shrub to ensure good air circulation.

Thank you very much. Is there any spray that might be effective? Also I assume pruning must be done quickly.

No chemical control is recommended. Fungicides are preventatives and will not control an existing problem. Prune during dry weather and thin to ensure good air circulation.