60 MASS. EXPERIMENT STATION BULLETIN 436 



Spy 227. At the same time buds from unbudded branches of the same tree of 

 strain R were set in other Spy 227 rootstocks. At the present writing two trees 

 of strain R have died in typical fashion, while all the trees of strain G are normal. 

 This suggests that the lethal factor cannot pass into strain G and that strain G 

 cannot communicate resistance to strain R; but the final conclusion cannot be 

 reached until more time has passed. 



Some trees of Starking grow very poorly on certain clonal rootstocks; they 

 blossom very early in life and may die or, in some cases, seem to recover and 

 grow better. Other trees of Starking grow normally on the same rootstock. 

 Three-year-old trees budded from such weak and vigorous trees of Starking 

 show the same difference. Those growing from weak trees are much less vigor- 

 ous and some will probably die, while buds from the vigorous trees are growing 

 normally. There seem to be two "strains" of Starking trees. Whether the 

 trouble is a virus is not known. 



Tree Characters of Fruit Varieties. (J. K. Shaw, A. P. French, O. C. Roberts, 

 and W. D. Weeks.) The study of new varieties is a task without end. In the 

 last report it was stated that Van Buren was the only bud sport that could be 

 distinguished from its supposed parent variety, Duchess of Oldenberg. An exam- 

 ination of the original tree of Van Buren and propagation of buds from a normal 

 branch and the sporting branch of this tree, and comparison with trees known to 

 be Duchess of Oldenberg, has revealed that the original tree is not Duchess of 

 Oldenberg but some other variety at present unknown. This single exception to 

 our usual experience that red bud sports cannot be distinguished from the parent 

 tree by nursery trees is thus removed and the general statement holds true. It 

 is not correct to call Van Buren the Van Buren Red Duchess. 



The inspection of nurseries for trueness-to-name was carried out in 1945 and 

 is now in progress for 1946 on a somewhat enlarged scale. 



A bulletin on the identification of blueberry varieties has been published. 



The Nature of Winter Hardiness in the Raspberry. (J. S. Bailey, A. P. French, 

 and R. A. Van Meter.) Canes of the six varieties, Marcy, Washington, Taylor, 

 Milton, Latham, and Chief, were forced in the greenhouse at weekly intervals 

 as in the fall ot 1944. Again Chief and Latham were the slowest to start; Marcy 

 and Washington started most readily; Milton and Taylor were intermediate. 

 Milton behaved about as in 1944 but Taylor started much more readily. The 

 rest period for all was over about a week later than in 1944. 



Although the winter of 1945-46 was not severe, a large amount of cane killing 

 occurred on all six varieties, undoubtedly' caused by a very heavy infection of 

 spur blight. Fermate sprays are being used to eliminate this source of trouble. 



Comparison of Cultivation and Sod Mulch in a Bearing Orchard. (J. K. Shaw.) 

 This project, which was started many years ago, has developed into a study of 

 the mineral nutrition of apple trees, with special emphasis on magnesium de- 

 ficiency and the value of orchard mulches. It is now planned to study the value 

 of mineral leaf analysis in planning a fertilizer program for orchards. When 

 unmistakable symptoms of a mineral deficiency appear, it is probable that much 

 injury to the tree has already occurred. A knowledge of the mineral content 

 of the leaf might suggest that certain elements were low and thus permit an 

 earlier diagnosis of an approaching deficiency. The value of branch injections 

 and leaf treatment as a means of diagnosis is also being studied. 



The project has led to a gradually increasing appreciation of the value of 

 potash and possibly phosphorus in the orchard; also to the belief that the so- 

 called "complete" fertilizer is not complete. Magnesium, boron, and possibly 

 calcium are as important as phosphorus and potassium to supplement the most 



