842 EXPEKIMENT STATION RECORD. [Vol. 43 



rusts to detennine the effect of temperature and supply of oxygen and water on 

 germination. The spores studied were found to germinate over a wide range 

 of temperature. The .neciospores of Cronurtmm ribicola germinated through a 

 range of 12° C, the urediniospores of the same fungus through a range of 

 17°, the seciospores of Gymno sporangium clavipes through a range of 20°, tlie 

 urediniospores of Puccinia antirrhini through a range of 15°, the teliospores of 

 P. malvaaearum through a range of 27°, and the urediniospores of Uromyces 

 cai-yophyllimis through a range of 25°. The germination of the spores of the 

 different species was found to decrease vei-y rapidly above and below the 

 optimum. 



The author claims that although spores may germinate over a wide range 

 of temperature there is a material degree of host infection only when the 

 temperature is near the optimum, and that the optimum temperature for the 

 germination of rust spores is relatively low. There is believed to be a relation 

 between the time of year when spores occur and the optimum temperature for 

 their germination. 



Wind and the distribvition of pathogenic soil organisms, H. G. MacMil- 

 LAN {Phytopathology, 9 (1919), No. 10, pp. 471-J/73, pi. i).— The author describes 

 conditions occurring in eastern Colorado in 1919 in parts where severe dust 

 storms occurred, and the observations are believed to indicate that wind is an 

 active agent in the distribution and dissemination of organisms present in the 

 soil and pathogenic to field and truclc crops. 



Insect carriers of plant diseases, E. M. DuPorte {Ann. Rpt. Quebec Soc, 

 Protect. Plants [e*c.], 11 {1918-19), pp. 59-65).— A consideration of the part 

 played by insects in the dissemination of plant diseases is said to show that a 

 large number of the most serious fungus diseases can be more effectively con- 

 trolled by insecticides than by fungicides. 



Some newer phases of disease and insect control, J. Oskamp {Trans. Ind. 

 Hort. Soc. 1918, pp. 33-42). — The last two or three years have been fruitful as 

 regards disease control suggestions and methods, largely due to the war, 

 directly or indirectly. 



The spray gun is regarded as a time saver, but of doubtful efficiency as com- 

 pared with the spray rod. Dry lime sulphur (which is essentially lime sulphur 

 evaporated to dryness under pressure and finely ground) proves reasonably 

 satisfactory. 



Calcium arsenate burning appears to be due to the free arsenic and is les- 

 sened by the addition of lime. Dusting experiments, while not very conclusive, 

 have given interesting results as regards Comparative costs and relative amounts ; 

 of materials and labor. Double strength lime sulphur has not shown any con- j 

 siderable value in controlling apple blotch. Rasplieny anthracnose is said to 

 have been controlled elsewhere with Bordeaux mixture (4:4:50) or lime 

 sulphur. 



Relative adhesiveness of the copper fungicides, O. Butlek and T. O. 

 Smith {Phytopathology, 9 {1919), No. 10, pp. 431-444 >' reprinted as New Hamp- 

 shire Sta. Sci. Contrib. IS {1919), pp. 4S1-444)- — A. report is given of studies 

 made of Bordeaux mixture. Burgundy mixture, copper acetate, and cupram- 

 monium sulphate to determine their adhesiveness. This was tested by spraying 

 Coleus plants which were allowed to stand 48 hours before they were rained on. 

 The plants were then dried and the adhesive qualities tested. 



Neutral and alkaline Burgundy mixtures were more adhesive than Bordeaux, 

 and alkaline Burgundy mixture was more adhesive than the neutral wash. 

 The adhesiveness of Bordeaux mixtures was found to vary with the different 

 formulas used in its manufacturing, and the effect of the temperature of the 



