We planted 3 forsythia bushes two years ago. Last year one died and we planted a new one in the same spot. This year another one of the original ones has many dead branches and I now see things on the branches/leaves, and it seems to be affecting the third of the original ones. All are still putting out new growth as well, but I'm thinking that the bushes are all infected with something. I'm attaching a few pictures of branches I cut off. Do you need pictures ofWhat do you think is wrong? Can we treat this? Thank you.
Harford County Maryland
It is possible that you may be dealing with a Twig Blight caused by Sclerotinia. This fungus is made worse by the wet conditions we are experiencing so far.
You can check some of the affected branches by pruning. Prune out an affected branch and split to look at the inside pith. The Black Sclerotinia sclerotium (overwintering structure) in the pith would look like a mouse dropping (black). Young nodules may be white at first.
The process to deal with this is to prune out infected branches, thin the plant to promote good air circulation. No chemical control is recommended.
See more https://extension.psu.edu/forsythia-diseases
Thank you. I read about Twig Blight, but didn't see any black nodules in the stems. Or do you not always see them? Here's another picture.
This pith appears normal, but it's possible the fungus has not produced visible structures here. Fortunately, Forsythia benefit from renewal pruning (hard cut-backs that remove most of the old growth), and should rebound well if no other issues are present. While fairly adaptable, Forsythia thrives in full sun and well-drained soil; last year's exceptionally wet spring and late-season drought may have caused some root loss that it is still recovering from. Root loss can also cause branch dieback, due to the insufficient healthy roots left to keep the tissues hydrated and nourished.
That's very helpful, thank you.