450 EXPERIMENT STATION RECORD. 



Black rot of tobacco, R. Rapaics (Magyar Dohdnynjsag, 30 (WIS), No. 4, 

 pp. 2-4; ads. in Internat. Inst. Agr. [JBome], Mo. Bui. Agr. Intel, and Plant 

 Diseases, 4 (191S), No. ^, p. 659). — A destructive disease attacking tobacco 

 duriug its fermentation and decomposing the leaves, said to be unknown in 

 Europe until recently, is reported from Hungary. The trouble is stated to be 

 due to the activity of Sterigmatocysiis { Aspergillus) nigra. No remedy has 

 as yet been announced. 



The mosaic disease of tobacco, H. A. Allaed (U. S. Dept. Agr. Bui. 40, pp. 

 SS, pis. 7). — The results of a preliminary series of investigations on the cause 

 of mosaic disease of tobacco and other solanaceous plants are given. 



This disease the author found was communicable to a large number of solana- 

 ceous plants but not to plants of other families. It is said to be quite simi- 

 lar to the mosaic disease of pokeweed. The mosaic virus permeates all parts 

 of the plant but does not infect the embryos of the seed; therefore such seed 

 will produce healthy plants. Once initiated, the disease becomes a progressive, 

 incurable malady. It was found possible to infect plants with the sap of 

 mosaic plants which had been passed through a filter. 



Certain species of aphids are considered active disseminators of the mosaic 

 disease, and observations made in the field show that they may sometimes be 

 responsible for the occurrence of the disease in the seed bed and its subsequent 

 spread in the field. In these experiments cutting back, repotting, or otherwise 

 subjecting plants to unfavorable conditions did not prove sufficient to produce 

 infectious mosaic symptoms. Physiological disturbances in the plants are not 

 believed to be an adequate cause of this disease, and the author believes that 

 organisms are its primary cause, although none have yet been isolated. 



A new disease of cucumbers, Altheimer (Prakt. Bl. Pfianzenl)au u. Scliutz, 

 n. ser., 11 (1913), No. 9, pp. 109-112). — The author reports the receipt from 

 Schwaben of cucumber leaves spotted by a fungus which is said to be identical 

 with Corynespora mazei (C. melonis), already destructive in England and 

 Holland. Its possibilities for harm are said to be great, especially where 

 phosphoric acid is lacking. It is said to be carried with the r*eed, and it is 

 recommended that the latter be treated with copper sulphate of 2 per cent 

 strength before bein^ used or shipped. 



Tomato rot, L. Pavaeino {Riv. Patol. Veg., 6 (WIS), No. 6, pp. 161-16S).— 

 The author states that tomato rot, noted by Groenewege (E. S. E., 29. p. 246) 

 as due to an organism described under the name Phytohacter lycopersicum 

 n. sp., is identical with that already described by himself (E. S. R., 25, p. 148) 

 and named Bacterium lyriosii n. sp, 



Experiments on the control of the cedar rust of apples, H. S. Reed, J. S. 

 CooLEY, and C. H. Ceablll (Virginia Sta. Bui. 203, pp. 28, figs. 11). — After 

 describing the cause of the rust of apples, symptoms, and effect, the authors 

 giire an account of spraying experiments carried on during 1911, 1912, and 1913, 



Lime sulphur, iron lime sulphur, copper lime sulphur, atomic sulphur, Bor- 

 deaux mixture, iron Bordeaux mixture, and mercuric bichlorid were tested, and 

 data are presented indicating the amount of reduction in disease, as shown by 

 leaf infections. The experiments indicate that certain spray materials have 

 great value in controlling cedar rust in the orchard, copper lime sulphur, a new 

 fungicide, being very efficient in this respect. Ordinary lime sulphur and Bor- 

 deaux mixture were also found to give good results. 



In the course of the experiments it was found that the maximum infection 

 takes place only during the very early stages of leaf development. If the 

 weather conditions are unsuitable for the development of sporidia, the infec- 

 tion win not appear on the earlier leaves. 



