248 EXPEEIMENT STATION EECORD. 



tion, through the possible injury of the bark, is thought to favor the entrance of 

 the organism. The propagation of orchard trees by root grafting is said to 

 favor this form of the trouble, as top-worked or budded trees do not appear 

 to be so commonly attacked. 



The authors discuss methods of dissemination, the organism being apparently 

 distributed largely by insects. 



For control, cutting out the blight and sterilizing the cut surfaces with cor- 

 rosive sublimate, after which the cut area is coated with white-lead paint, are 

 recommended. 



A brief description is given of blossom blight, fruit blight, twig blight, and 

 canker blight, which are due to the same organism as that causing collar blight 

 and which occur on apple, pear, and quince trees. 



A bacterial disease of stone fruits, F. M. Rolfs (New York Cornell Sta. 

 Mem. 8 (.1915), pp. 375-436, figs. 12). — In this publication, which is also a thesis 

 for the degree of doctor of philosophy in Cornell University, the author de- 

 scribes a bacterial disease of stone fruits due to Bacterium pritni. 



Cultivated varieties of the apricot, nectarine, peach, and .several varieties 

 of plum are affected by this disease, various names being given to it, such as 

 leaf spot and shot hole on the leaves, black spot and crack of the fruit, black 

 spot and black tip of the young twigs, and bacterial canker when the disease 

 occurs as open perennial wounds on branches. The trouble is reported from 

 20 States, extending from Connecticut to Florida and westward as far as Kansas, 

 Oklahoma, and Texas. 



The symptoms of the disease are described at length, after which the mor- 

 phology and cultural relations of the organism are given. Attention is called 

 to the varying resistance of different varieties to attack, the majority of Ameri- 

 can varieties suffering but little, while nearly all Japanese varieties of plum 

 are very subject to the disease. Other host plants show similar differences 

 in susceptibility. 



Experiments for the prevention of the disease indicate that Bordeaux mixture 

 will control it, but as the foliage of the peach and nectarine is specially sensitive 

 to the action of copper salts, these must be greatly reduced. Self-boiled lime 

 sulphur alone was found to be much less effective than Bordeaux mixture, but 

 after 2 lbs. of arsenate of lead was added to 50 gal. of the lime sulphur it be- 

 came much more effective. 



For the control of this disease the author recommends careful selection of 

 stock, the cutting out of old neglected trees where young trees are being planted, 

 thorough preparation of the soil, and complete fertilization, together with the 

 spraying. 



A bibliography is given. 



Little leaf (California Sta. Rpt. 1915, pp. 10, 11). — A disease designated as 

 little leaf is said to attack different kinds of trees and is particularly serious 

 on peaches in the San Joaquin Valley. 



An investigation has been made of the trouble, and the results thus far ob- 

 tained indicate that it is accompanied by a lack of available nitrogen in the 

 soil. This may be due to a lack of total nitrogen or to a lack of nitrifying 

 power. 



Abnormal bacterial conditions have been found in soils in connection with 

 this disease, as well as dieback and mottled leaf, and this has led Lipman to 

 conclude that these physiological diseases are probably associated with weak 

 nitrifying power of the soil (E. S. R., 33, p. 740). 



Fall spraying for peach leaf curl, D. Reddick and L. A. Toan (New York 

 Cornell Sta. Circ. 31 (1915), pp. 65-73, fig. 1). — An account is given of spraying 

 of peach orchards for the control of leaf curl, lime-sulphur solution being used 



