Dear UBC Botantical Garden, I am see a terrible slow death of my cherry tree. It seems there is a yellow fungus and sometimes it balls up and I cut it off then it comes back after a year. Would anyone know what it is and how to treat ? Pictures attached. I live in San Jose CA.
Hi Dave, Would you be able to add a close-up shot if your camera has magnification? I’ll take another look when I get home - from a proper monitor rather than a cell phone
@Dave Takada - even on a larger monitor I can't see enough detail for ID: If you are able to add a photo at a higher magnification that would be helpful, thanks.
Hello, thank you for your reply. I was able to take another pic, this is as close as I can reach. I hope this helps ?
Thanks for adding closer shots @Dave Takada, much appreciated. Unfortunately a bit too blurry to be able to give you a positive ID, but it is possible that this is a lichen not a fungus, and if so, likely Weedy Sunburst aka Xanthoria parietina. - The colour, the suggestion of having flat lobes with smooth margins, and the overal grown pattern on the bark suggest this could be this lichen. You can test this by trying to peel some of it away from the shrub, and looking closely to see if it is thin/leafy and growing attached to the surface (lichen) or emerging from under the bark via small crack or hole in the bark, as a gelatinous semi-translucent set of lumps (fungus). If it is a lichen then the lichen is not hurting your shrub. It is however taking advantage of the opportunity to colonize a substrate with sun access, in order to photosynthesize. When a lichen inhabits a defoliated branch, that means something else - virus, fungi, bacterial infection, oomycete, etc - has damaged the shrub/tree and the lichen is simply taking advantage of the resulting space created. If it turns out to be a fungus, the colour suggests one of the yellow/orange group of jelly fungi. If that turns out to be the case, the body of the fungus is inside the shrub and you are just seeing the fruiting bodies. If you check this and other branches you might see parchment/crust fungi fruiting bodies, associates of the jelly. If it is a fungus - I don't have the plant pathology experience to give you the best advice around potential mitigation - perhaps others will chime in - but you could try severing the affected branches as some kinds of fungi can have their spread stopped that way. I see that done on street cherry/plum trees sometimes, so I assume it works sometimes. I hope that help & I hope for the sake of your cherry that it is a lichen. - frog
