Why Would Walnuts Be Moldy On The Inside When Cracked?

Question

We bought property with 2 mature grafted walnut trees. We didn’t have any fruit last year because of a late spring freeze. This year, we had plenty of nuts, but when cracking them open, 80% of them were moldy on the inside. No sign of breach in the shells. What would cause this? Is there any way to keep it from happening next year?

Answer 1

It sounds like a very common Walnut blight, Xanthomonas juglandis

This website will help: https://www2.ipm.ucanr.edu/agriculture/walnut/Walnut-Blight/

This article will help with fungicide use: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm