How do I treat a Japanese lilac tree that seems to have a fungus?

Asked April 12, 2014, 10:15 AM EDT

I have a Japanese lilac tree that looks like it has some type of fungus. It started to split at the base, and a white substance was inside the split. It has since began to split farther up, and a few branches produced very little foliage. I sprayed a fungicide on it, but it did little good. Do I need to put something in the soil?

Carver County Minnesota

4 Responses

How to Recognize Sapwood Rotting Fungi Gardeners often first notice dead branches throughout the canopy of infected trees. Cracked and peeling bark may be seen on the main trunk or branches. Upon close examination, clusters of small white shelf fungi can be found growing on the infected wood. These are reproductive structures of the sapwood rotting fungi and can be easily seen this time of year in Minnesota. A gardener can determine which of the two fungi is causing the problem by closely examining these fungal spore producing structures. Photo 2: Spore producing structures of Cerrena unicolor Photo by M.Grabowski UMN Extension . The spore producing structures of Cerrena unicolor are ½ to 3 inch semi circular shelf fungi. They are white to green gray in color and often rings of growth are apparent on the top surface of the fungi. Photo 3: Spore producing structures of Schizophyllum commune Photo by M.Grabowski UMN Extension. Teeth like ridges can be seen on the lower surface of the fungi. Schizophyllum commune also produces small shelf fungi on infected wood. These shelf fungi are smaller (1/4th to 2 inches across), cupped downward, and pure white. When examined up close, the upper surface appears fuzzy. Gills can be seen on the lower surface of these shelf fungi. Keep Trees Healthy and Strong to Avoid Sapwood Rotting Fungi Prevention is the best management strategy to control sapwood rotting fungi. Avoid wounding trees with weed whips, lawn mowers or other lawn equipment. If trees are damaged in a storm or by ice, remove broken and cracked branches with a clean pruning cut. This cut will be easier for the tree to heal than a long jagged rip caused by a storm. Water trees during times of drought. Mulching the base of the tree out to the canopy drip line with an organic mulch like wood chips can help maintain soil moisture and reduce competition with turf grass. If infection appears on a branch, prune the infected branch on a cool dry day and remove it from the area. If the infection appears in the main trunk, the only thing that can be done is to reduce stress on the tree and hope for the best.

This is a white flat substance, there is no shelf. I wish I knew how to send a picture of it, but I don't think the fungi you suggested is right.

I just googled sapwood rot and it doesn't look like that at all. It is very white and flat.

You may want to consult and arborist, who can diagnose the problem and recommend treatment based on what they see.