Problems with English walnuts in Lane County - Ask Extension
We have two English walnut trees on our property west of Eugene, one that is about 80 years old and another about 50. The older tree produced well in...
Knowledgebase
Problems with English walnuts in Lane County #879958
Asked August 02, 2024, 5:04 PM EDT
We have two English walnut trees on our property west of Eugene, one that is about 80 years old and another about 50. The older tree produced well in the past, the best harvest maybe 12-15 years ago. Each year it develops nuts, but at harvest time the nut "meat" is black and almost entirely inedible. The younger tree continues to develop more nuts each year, but at harvest time it too has only inedible, black nut "meat."
I heard that this could be the result of too much nitrogen in the ground where the trees are growing. I wonder if this could be the case, and if it could be caused by farm animals pasturing in the area where the trees grow. Could someone give me more information about this problem? Thank you
Lane County Oregon
Expert Response
Have you taken a soil or leaf tissue test that show excess levels of nitrogen? There are some other possible causes, such as walnut blight that can result in the nuts, or meats, to turn black. With pathogens, you would likely see other symptoms such as leaf spots or spots or staining on the husks. Do you see other symptoms? Are the discolored nuts hard or soft (i.e. are they black and mushy)? If you could provide a description or some photos of the symptoms, that would be helpful.
