Pest or disease in almond tree
Hi, I have a ~5 year old Hall's Hardy almond in my yard in North Portland, and it seems to have signs of either a borer infestation or gummosis. Can you confirm which for me (photo attached), and possibly point me to sources for organic controls? I have just planted two cherry trees nearby and would like to understand how to keep protect those as well. Thanks very much for any help you can offer.
Well the gummosis could indicate a number of different problems including environmental damage, physical wounding, disease, insects (borer), or stress. Having it just above the soil line could indicate borer, but I cannot tell from the photo. There
does appear to be a canker or dead tissue around the base of the tree below the gummosis, so there may be a disease at work. Scrape some of the bark off just above the soil line. Is the cambium bright green or is it dead?
A good reference on gummosis is here: https://extension.tennessee.edu/mtnpi/Documents/handouts/Insect%20and%20Disease%20Control/Gummosis_in_Prunus.pdf
Bacterial canker would be strong contender: https://pnwhandbooks.org/plantdisease/host-disease/cherry-prunus-spp-bacterial-canker
See also this article about gumming in prunus: https://pnwhandbooks.org/plantdisease/host-disease/cherry-prunus-spp-gumming
I would also recommend digging around in those wounds for peachtree borer larvae. If found, they should be killed. This article suggests appropriate management if borer turns out to be the problem. See: https://pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/peach-flowering-prunus-peachtree-borer