This topic will largely be left for future discussion under another subject, but it occurs to me that much might be accomplished by proper attention to nutrition, especially when setting out trees for grafting, selection of proper site, fertility of soil, cultivation to aid absorption, etc. I have observed limbs of animals much smaller than normal due to prohibited movements or lack of proper circulation, one side of a tree developed out of proportion, eggs without hard shell due to lack of calcium in the hen's diet, and I know of an old English walnut tree that bears nuts with shells so thin as to be almost negligible. I am told that at one time this tree bore a nut with a much thicker shell. It has never had any attention and it is quite probable that the lack of proper shell building elements causes the trouble. I have grafted a few of these and I want to see what happens by furnishing better nutrition.
Concerning scion wood, I have "ringed" some limbs, similar to the method used sometimes in producing extra large fruit, in an effort to have the scion store up a large amount of nutrition. This experiment I shall continue in the spring.
This article is based entirely on my own ideas, observations and conclusions in connection with old standing principles. As previously stated, I claim nothing new and my only desire is to stimulate others to make like observations.
Carrying out my conclusions in my work next spring I propose to cut the tops out of all my trees, leaving a few lower limbs instead of the top ones, allow them to start growth a little before grafting, pinch the tip from that growth, and, in addition to covering with paraffin or some combination of it, shade the scions on the south-west side, either by tipping branches over them or some other way. Paper bags seem to absorb the paraffin. Double grafting in the case of the Vest and the Weiker will be tried. Whitewashing the stock to prevent sun burn will be used where necessary. Several other experiments based on the idea of cellular stimulation before the scions are placed in position will be tried.
Dr. M. B. Waite, of the Federal Insecticide and Fungicide Board, U. S.
Department of Agriculture, spoke as follows:
DR. WAITE: Some of you may recall that several years ago, when you were meeting here in this hall, I gave you a paper on the nut diseases of the northeastern part of the United States, and it would not be desirable to go over that same ground again. At that time, we took up the bacteriosis of the Persian Walnut, and filbert blight, and I outlined a program of proposed treatment for the filbert blight. It might be interesting to note here that Dr. Morris, and I believe also Mr. Bean, put that treatment into practice with success. The situation still remains, however, that we do not know of diseased plantings of any size. If we find a real plantation of filberts we will be glad to attempt control measures ourselves. I have planted about two dozen filberts and they still remain free from the disease. There are very few local hazel nuts, wild or cultivated, around Washington; but we understand that the few hazel nuts are free from this disease.
There are two or three things I wish to mention. One is the repeated inquiries reaching my office with regard to the non-filling of nuts, mostly the cultivated nuts, sometimes the pecan, sometimes the black walnut, and frequently the English walnut. The subject is a complicated one and the disease is not one that we can put under the microscope and diagnose at once. The trouble is due to a complex of varietal and environmental conditions, the effect of the conditions of growth, of soil fertility, temperature, soil, water and humidity, sunshine, etc., on that plant. Very often it is because people get the wrong variety and do not know what they have. They may have an unproductive seedling.
On the other hand a good variety may fail to bear in a locality where it is not suited. Very frequently the real lack is in soil fertility. Of course the success of the pecan trees down South around pig pens is an old joke to you gentlemen, but there is truth in that. For good nuts there is often need for a little extra manure or fertilizer, or perhaps both. Sometimes there are rich pockets in the earth where those trees would like to grow, or rich bottom lands which will produce without manure. I think one of the best ways is to fertilize with manure, if possible. Pollination troubles in connection with the non-filling and dropping of the nuts should be thought of.
Then there is another angle to be considered, and perhaps I can express it most definitely to you by citing the example of the June drop of peaches. Whenever a tree, like the peach tree or the pecan or the black walnut, sets its fruit in the spring, you will find that there are cross-pollinated and self-pollinated fruits. These will begin to drop their nuts or their fruit at definite stages. Furthermore we will find the abortive seeds are not one size. This means that there were definite stages of the pollination and of the fertilization. I should like to work that up and find what the stages are.
The last big step in the dropping of the peach tree is the shedding of the fruit just as the pits are hardening. When they are hard the fruit does not fall. So this June-drop question ties in with the complications of pollination and nutrition. We know from experiments on the sterility of the pear tree, if highly fed and cultivated, such as those I worked on in the city of Rochester, that those highly fed trees will have some self-fertilized pears. In all of the pears we got no pears resulted when pollinized with the pollen of the same variety, except on those well fed trees. We learned this in the East, and have since found the same type of self-fertilized pear occurring naturally in California and other places in the West. In nut production that whole question of setting and filling is tied up in a complicated way with pollination and nutrition.