72 



drop their nuts or their fruit at definite stages. Furthermore we will 

 find the obartiM' seeds are not one size. Tiiis means thit there were 

 definite stages of the j)ollination and of the fertilization. I should like 

 to work that up and find what the stages are. 



The hist big step in the dropping of the pc.ich tree is the shed- 

 ding of the fruit just as the |)its are hardening. When the}' are hard 

 the fruit does not fall. So this June-drop question ties in with the 

 complications of polliu tion and nutrition. We know from exiieriments 

 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 jiollinized 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 ])ear occurring naturally 

 in California and other places in tiie AVest. In nut production that 

 whole question of setting and filling is tied up in a complicated way 

 with pollination and nutrition. 



Aside from nutrition the other thinu' to he 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 1 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 fre- 

 quently have, we find that the English walnut suffers more from 

 winter-killing right around Washington, D. C and in Pennsylvania, 

 than up iri Rochester; and we also have complaints of winter-killing as 

 far south as Georgia. A common cause is the variation of moisture. 

 After a dr}' 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 thev should be drving 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 mlay have this trouble with the pecan, 

 young trees two and three years old, and I have photographed them. 



