146 EXPERIMENT STATION EECOED. 



Some observations on a peculiar soil disease, W. E. Collinge {Jour. Bd. 

 Agr. [London], 20 U914), Ko. 10, pp. 875-879 ) .—The author reports experi- 

 ments in treating plats that had shown abnormal conditions and lowered 

 returns during some yenrs of cultivation in wheat, oats, rye, mangolds, and 

 potatoes. Unslaked lime. 12 to 15 cwt. per acre, showed little or no improve- 

 ment, but with sulphur at from 4 to 6 cwt. per acre there were produced normal 

 or improved crops. The use of 8 cwt. killed many of the plants. Untreated 

 plats showed steady deterioration from year to year. 



The author thinks this disease may be due to bacteria which interfere with 

 the nutrition of the plant ; but he refers, in this connection, to the contributions 

 of Russell and Hutchison, dealing with the alleged influence of protozoa in the 

 soil (E. S. R., 22, p. 121; 24, p. 621). 



Injury by smelter smoke in southeastern Tennessee, G. G. Hedgcock {Jour. 

 Wash. Acad. ScL, // {1914), No. 4, pp. 70, 71). — The author states that the 

 injury to vegetation in this region still extends in the same genei-al direction 

 from the sources of injurious gases as reported by Haywood (E. S. R., 19, p. 

 222; 23, p. 430), the slightly lower degree of injury corresponding to the ob- 

 served greater extension in area. Prevailing winds are important or decisive 

 factors as to distance and direction. The injury is most severe with conifers 

 and in upland regions. Garden beans, which are especially susceptible, afford 

 a delicate index as to the direction and distance of extension. The injury, 

 which is attributed mainly to sulphur dioxid, shows characteristic features and 

 the various trees affected show resistance thereto in a definite order, which is 

 set forth. 



A study in cereal rusts, physiological races, E. C. Stakman {Minnesota 

 8ta. Bui. 138 {1914), pp. 56, j^ls. 9). — The author presents the results of an 

 investigation undertaken with the object of determining the possibility of devel- 

 oping and breaking down physiological races of rusts as well as obtaining infor- 

 mation concerning some of the factors influencing varying resistance in immune 

 or semi-immune varieties of wheat. 



Inoculation experiments were carried on with Puccinia graminis hordei, P. 

 graminis avence, P. graminis secalis, and P. graminis tritici obtained from their 

 respective hosts in the fields at the station and cultivated through at least a 

 dozen successive transfer generations. In nearly all of the experiments with 

 biologic forms the rust had been confined to its own host for at least 20 genera- 

 tions. Spores of the rusts were placed on leaves of various varieties of wheat, 

 barley, oats, rye, eiukorn, and emmer, after which the conditions were made as 

 favorable as possible for the development of the fungus, either by producing a 

 high moisture condition or the use of anesthetics, excessive fertilization, leaf 

 injury, etc. 



It was found that direct tranfsfers of P. graminis may be made from oats to 

 wheat and rye. The rusts from oats and barley used in the experiments could 

 be readily transferred to rye. The use of anesthetics had some effect in render- 

 ing an immune plant slightly more susceptible to rust, while leaf injury appar- 

 ently had no effect. High fertilization, by increasing the virulence of the attack 

 on semi-immune forms, is thought to have some influence in breaking down 

 biologic forms. The author found that there was apparently a physiological 

 and probably a slight morphological change in the rust fungus when grown 

 continuously on a semi-immune host, the change manifesting itself, however, 

 very gradually as an adaptation to the new host. It is believed that biologic 

 forms of cereal rusts, at least P. graminis tritioi, do not lose their specialization 

 tendencies when grown on barberry. The degree of incompatibility of host and 

 parasite was found to vary greatly. In semicompatible forms comparatively 



