446 EXPERIMENT STATION RECORD. 



Downy mildew and measures for combating it, Y. Mabtinand (Rev. Vit., 

 J/1 {191 'i). No. 1011, pp. 707-710). — A discussion is fe'iven of the role of rain, 

 dew, and fog in the dissomination of the spores of the downy mildew of grapes. 



The diseases of the sweet pea, J. J. Taubknhaus (Delaware 8ta. Bill. 106 

 (IDl/f), pp. 93, figs. JfS). — This bulletin, which was also presented as a thesis 

 to tlie Graduate School of the University of Pennsylvania, embodies the 

 results of the autlior's studies on the diseases of sweet peas. Some of the 

 conclusions have been previously noted (E. S. R., 20, pp. 352, Or»0). In the 

 bulletin llie author considers the diseases under the heads of fungus, bacterial, 

 and physiological diseases, discussing those which have attacked different 

 parts of the plant. 



Among his conclusions the author states that the disease known as streak 

 in England is due to Bacillus lathyri and not Thielavia hasicola, as has been 

 claimed (E. S. R., 26, p. 551). 



In connection with these investigations the pathogenic nature of Corticium 

 vagiim has been established, and Cha'tomiutn .^pirochcetc has been shown to 

 produce a root rot of the sweet pea. A Fusarium disease is described, and the 

 name F. lathyri n. sp. has been given the organism causing it. 



Among the animal parasites of the sweet pea the nematode ITctcrodera 

 radicicola is described, and it is said that this pai'asite is associated with 

 several fungus diseases. A collar rot as well as a stem disease of the sweet 

 pea, due to Sclerotinia lihertiana, are described for the first time. 



A mildew of the sweet pea, which is very prevalent under greenhouse con- 

 ditions, has been studied. This is due to a species of Oidium. The perfect 

 stage has not yet been found. 



The relation of GlomercUa rufomaciilans, the cause of the anthracnose of 

 the sweet pea, to species of this fungus on other hosts is discussed at some 

 length. The author has shown the pathogenicity and infectious nature of the 

 mosaic disease, which is considered as probably due to bacteria or protozoa 

 which present methods of investigation are not able to detect. A disease known 

 as bud drop is described, which is said to be induced by a high nitrogen supply 

 which is not properly balanced by phosphoric acid and potash. 



Under methods of control attention is called to the fact that certain indi- 

 viduals are more immune to anthracnose than others, although no one variety 

 seems particular!}' nonsuscei)tible. 



Experiments are reported in which boiling seeds for one or two seconds, 

 soaking them in sulphuric acid, or soaking in 5 per cent formaldehyde solution 

 showed that all of these treatments would destroy the spores of parasitic 

 fungi without injury to germination. Soaking seeds in sulphui'ic acid inci-eased 

 the percentage of germination. 



Watering soils with chemical solutions is said not to increase the resistance 

 of plants grown in that soil. 



A method has been devised for deteinnining the length of time which any 

 fungicide can remain efhcient in conti'olling plant diseases when sprayed on 

 the plant to be treated. This consists essentially of siiraying the fungicides on 

 a large mimber of slides which are dried and divided into different lots and 

 germination tested at definite intervals. 



A bibliography of the subject is given. 



The chestnut blight fungus and a related saprophyte. P. J. and H. W. 

 Anderson (Pcnn. Chestnut Tree might Com. Bui. Jf (1913). pp. 26, figs. 6).— 

 The substMuce of this bulletin has alreadj' been noted from another source 

 (E. S. R., 28, p. 551). 



