Effects of the Walnut Blight
In some seasons the walnut suffers from a blight that very seriously injures the crop. The picture shows samples of nuts ruined by the blight in a recent year. Mr. Burbank's selective experiments, as the reader is aware, are always conducted with an eye to producing varieties that are relatively immune to the attacks of fungous pests. Such specimens as these would obviously be avoided in all breeding experiments.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 11 Chapter 2