Aside from nutrition the other thing to be considered is that of disease. The common black walnut around Washington is generally poor from fungus leaf diseases. Those of us familiar with it around here know that they do not fruit well. This is not a good place for the common black walnut. The wild ones are nearly all poor. I was raised in the Mississippi Valley, where there were large nuts and fine ones, and we gathered those which fell from the specially good trees. They do not grow so well here, except the Stabler and a few others.
Leaving that subject, there is another I wish to take up. That is, the great number of complaints about winter-killing of the English walnut. Wherever we have been able to trace that down, as we frequently have, we find that the English walnut suffers more from winter-killing right around Washington, D. C., and in Pennsylvania, than up in Rochester; and we also have complaints of winter-killing as far south as Georgia. A common cause is the variation of moisture. After a dry spring and early summer soaking rains come in August and September, and the trees, brought suddenly into growth at the close of the season, when they should be drying out, the walnut tree in particular, show winter-killing. So I think one of the main troubles with the English walnut in the Eastern United States is the winter-killing. Even in Georgia we may have this trouble with the pecan, young trees two and three years old, and I have photographed them.
As to false stimulation, in the woods, where these trees grow native and under the conditions to which they are necessarily adapted, they are mulched and crowded when young by their competitors. In cultivation we do not get the crowding and the mulching that makes steady growth and proper ripening. So you should, by some process, growing corn, cover crops, or other trees, keep your delicate nut trees a little crowded and, if possible, mulched while young; and then later, cut out the undesirable things and let the trees have room.
I am not fully prepared to speak about the nut work of the Bureau of Plant Industry, because that should be handled by the chief of the bureau. I have charge only of the diseases of fruits and nuts. We have had $8,200 allotted to the project and will have $2,000 more this year, making $10,200. Originally that was $3,000 for nut diseases all over the United States. We started to work mainly on the southern pecan diseases, and partly on the bacteriosis of the walnuts of the United States. But the Southern Pecan Growers' Association got some additional money for the bureau, $5,000 of which was given to the fruit disease investigations, and was tied up with the other $3,000. But the wording of the bill said, "All for pecan diseases." So we transferred more to the project and made it $8,200 for the nut diseases. That means we have done very little work for the nut diseases except on Southern pecans, and I have been warned that one must not stress southern pecans with the Northern Nut Growers' Association.
We have had, however, one man, and will have two men, on the southern pecan diseases in Georgia, on pecan scab and pecan leaf diseases, who are winning out beautifully, and have nearly solved many of the problems, including the pecan scab. One of the difficulties is the occasional late summer rainy spell, bringing diseases and bad conditions. But in general we have solved the problem pretty well.
Then we have the more permanently dangerous disease, pecan rosette, which has taken about half of the pecans in some sections of the South, especially in south Georgia and in Florida. That disease is being experimented upon in the most extensive way of any of our projects. There is only one word to say about pecan rosette, and that is—humus—the disease is cured by the application of humus.
MR. REED: How far north is the walnut rosette disease?
DR. WAITE: As far as Falls Church, Va., but not much in the North.
MR. REED: The question was asked yesterday as to whether it could not be overcome in this latitude.
DR. WAITE: That nobody knows. The soils east and south of Washington are all acid, and the conditions are wrong for rosette. The soils have no tendency to chlorosis. They are, in fact, antichlorotic. Theoretically you could get the rosette conditions in the Piedmont region, but you are almost certain not to find them over this way.