DISEASES OF PLANTS. 147 



powdery scab of potatoes, discovered in New York State in June, 1914. and at 

 present thought to be confined to the counties of Franklin and Clinton. 



The disease is contrasted with common scab. It seems to be favored by low, 

 wet. alkaline soils and to be made worse by the use of lime. 



Field studies of the crown gall of sugar beets, C. O. Townsend {U. S. 

 Dept. Agr. Bui. 203 {1915), pp. 8, pis. 2, fig. i).— The results are given of a 

 study of galls produced on sugar beets, two distinct types being recognized 

 which are caused by bacteria. One of these forms is said "to be due to Bac- 

 ierivm tumefaciens, while the other is produced by B. heticolum. 



The effect of galls on the sugar content of beets was studied, and it was 

 found that the gall tissue was very low in sugar content and in purity and that 

 therefore their presence is detrimental. Sugar beet galls are said to sometimes 

 cause the beet roots to decay, but so far as general field observations can de- 

 lerniire, they do not appear to otherwise affect the tonnage. 



The author states that the disease may be held in check by a proper system 

 of rotation with grain crops. 



Potato and tomato diseases, E. Molinas {Prog. Agr. et Vit. (Ed. VEst- 

 Centre), 35 (WU), No. 26, pp. 813-818, figs. 3).— This is a brief discussion of 

 several potato and tomato diseases of bacterial or fungus causation, and of 

 sonje preventive or remedial measures recommended. 



Wart disease of potatoes, W. Cuthbkrtson (Gard. Chron., S. sei'., 51 {1915), 

 No. 1469, pp. 97, 98, fig. 1). — ^This is a brief historical sketch of potato canker, 

 noting some cases of infection showing the dangerous character of the disease, 

 also some cases of apparent breakdown of resistance, with a list of known re- 

 sistant varieties recommended for planting on suspected soil. Nearly all of 

 such varieties are white flowered. 



Phoma destriictiva, the cause of a fruit rot of the tomato, Claka. O. Jamie- 

 sox iV. S. Dept. Agr., Jour. Agr. Research, Jf {1915), No. 1, pp. 1-20, pis. 8). — 

 The author reports receipt of specimens of tomatoes affected with fruit rot 

 from Florida in March, 1912, which led to an investigation of the cause of the 

 trouble. 



When received, some of the fruit was green, some ripe, and some just begin- 

 ning to color, but most of the tomatoes had conspicuous dark spots on the side 

 and stem end. A microscopic examination of the tissues showed the presence 

 of a fungus, which has been isolated, and by means of infection experiments the 

 disease has been produced on green and ripe fruit and foliage in the greenhouse 

 and upon tomato plants in the field. Cross inoculations between the tomato 

 fruit and leaf have shown that the trouble was caused in both organs by the 

 same fungus. 



Inoculation experiments with the organisms were made on eggplant, potato, 

 sugar beet, Jimson weed, garden pea, bean, and pepper plants, but only on the 

 eggplant and potato were any infections obtained. 



A technical description of the fungus causing the disease is given. The 

 fungus has been proved to be an active wound jiarasite of green and ripe to- 

 mato fruit and also capable of causing leaf spotting of tomato and potato 

 plants. 



Blue mold in tobacco, T. A. J. Smith {Jour. Dept. Agr. Victoria, 12 (1914), 

 No. 11, pp. 641-643). — The author states that considerable loss is sustained 

 in Victoria by the attacks of the blue mold {Peronospora liyocyami) in seed beds. 



Accounts of some investigations for the control of this trouble are given, in 

 which formalin, toluol, boiling water, and lime were applied to plats with 

 satisfactory results. All of the seed beds in the experiments were covered 



