744 EXPERIMENT STATION EECOED. 



The author is of the opinion that an academic knowledge of mycology alone 

 is of comparatively little value from the standpoint of arresting plant diseases, 

 owing to the large number of factors which may be operative. 



The claim recently made, on the basis of a study of silver leaf disease, that 

 this disease may apparently be due at times to the fungus Stereum purpnrcum 

 and at others to undetermined physiological causes, is regarded as justifying 

 alarm if it proves to be indicative of a possibility more or less general. 



Plant diseases, J. C. Arthxjr (Indiann Sta. Rpt. 1915, pp. 29-31). — ^The author 

 briefly reviews the investigations in plant diseases conducted during the year 

 covered by the report. These include studies on grass and sedge rusts, control 

 of oat smut and potato scab, soil sanitation, and the results of a plant disease 

 survey of the State. 



In connection with the work on control of oat smut, various forms of machines 

 for treating the grain have been tested, some of them with considerable success. 

 Further experiments with liydrogen peroxid for the prevention of stinking 

 smut of wheat and smut of oats indicate that this chemical can not be used 

 effectively as a grain disinfectant. 



In the notes from the plant disease survey, a dozen or more diseases are 

 reported for the first time as occurring in this State. 



[Report of the research assistant in plant pathology], G. H. Coons (MMii- 

 gan Sta. Rpt. 1915, pp. 213-215). — One of the principal studies of the year 

 reported was that a serious canker of apple due to Plcnodomns sp., a portion of 

 which has already been reported upon (E. S. R.. 34, p. 647). 



Among reports of other investigations, an account is given of experiments on 

 potato seed treatment, the results confirming those previously noted (E. S. R., 

 31, p. 543). A disease of celery characterized by stmited growth is briefly 

 described. This trouble is said to be serious in a number of centers of celery 

 production, in some cases causing almost total loss. As a result of this study, 

 the author considers the disease of bacterial causation. Attempts were made 

 to determine control measures, and among the most promising was soil 

 sterilization. 



Diseases and enemies of cultivated plants in the Dutch East Indies, 

 A. A. L. Rutgers (Dcpt. Landh., Ni}i\ en Handel [Duieh Eaxt Incites]. Mcded. 

 Lah. Planienziekten, No. 9 (191^), pp. 2Ji). — Notes are given on diseases of 

 plants as observed, including Phytophthom fabeii, CortirUini mlmonienlor, C. 

 jamnicnm, Fomeft ,9emitostuft, HiimenoelKrte noxin, Thiiridaria tarda, and Phyl- 

 losticta sp. on rublxM- trees; a leaf curl and a bacterial disease of peanuts; 

 Piricularia and Helminthosporium on rice; rhytophthora on tobacco; Helopeltis, 

 Pestalozzia, L.'estadia. Cephalenros fireseen.<t, Nectria. Corticium, and Hypoch- 

 nus on tea; Corticium jaiianieum, Colletotrichum, and Hemileia vastatrix on 

 coffee; and diseases of unspecified causation, besides a number of insect ene- 

 mies of cultivated plants. 



A list of related publications issued in 1913 is also given. 



Germination conditions of teleutospores of TJredinese. Ill, P. Dtetel 

 {CcnIhL Bald, [etc.'], 2. Aht., Ji2 {1915), Xo. 25. pp. 698-705).— \n 0(intinuan<-e of 

 previous work (E. S. R.. 28. p. 241), the author has found that spores of Pue- 

 cinia malvacearum on mallow require for entirely normal development an 

 atmosphere fully saturated with water vapor. It is stated that the period of 

 exposure to unsaturated air necessary to complete loss of germinability is short- 

 ened as the humidity decreases. 



Recent data and questions regarding smoke injury to plants, F. W. Neoer 

 (Natvrw. Wchnsclir., 29 (1914). No. 3Jf. pp. 529-53^^ fl(}.<t. 5).—'V\\\s is a con- 

 densed account, with a brief bibliography, of observations on gases injurious 



