350 EXPERIMENT STATION RECOED. [Vol. S5 



In studying the meteorological conditions in connection with outbreaks of 

 this disease, the author claims that the climatic conditions in Iowa are gen- 

 erally unfavorable to such outbreaks, but that they sometimes cause serious 

 loss. The climatic conditions under which late blight occurs in Iowa are a 

 high degree of humidity with heavy dews and midsummer temperatures lower 

 than usual. An excess of rainfall and a predominance of cloudy weather are 

 predisposing factors. 



Some notes are given on disease-resistant varieties, the spread of the disease 

 through seed infection, storage qualities of infected potatoes, and the effect of 

 time of planting on the degree of injury. Diseased potatoes, it is claimed, may 

 be held in storage at a very slight loss from dry rot if the temperature is 

 sufficiently low and the potatoes are taken out of storage only a short time 

 before they are used. Early planting and the use of Bordeaux mixture are 

 considered effective measures for preventing late blight in Iowa. 



Straight head in rice, F. C. Quereau {Louisiana Stas. Rpt. 1915, p. SI). — 

 The author gives a brief account of a disease or condition in rice which seems 

 to occur on soils containing an abundance of vegetable matter. It is not defi- 

 nitely known whether the disease is due to physical conditions or to some 

 specific organism. The only preventive treatment at present known is to delay 

 the initial irrigation as long as possible, or, if necessary to irrigate because 

 of weeds or grass, to drain the land about 15 days after the first flooding, 

 allowing it to become perfectly dry. In a number of cases, this treatment Is 

 said to have prevented the condition designated as straight head. 



A disease of sugar beets, P. Berth axjlt {Jour. Agr. Prat., n. set.. 28 {1915), 

 No. 56, pp. 550, 551, figs. 2). — It is stated that In the region around Paris and 

 northward, industries dependent upon the sugar-beet crop have been consid- 

 erably affected of late by the development of unusual virulence in the attacks 

 of Cercospora beticola, which has previously appeared in this district but gen- 

 erally in mild form. Changes in coloration and inferior growth are as.sociated 

 with injuries to the leaf tissue. 



Cercospora beticola attacking sugar beets, K. Safllakd {Compt. Rend. Acad. 

 Sci. [Paris], 162 {1916), No. 1, pp. 47-49). — The author discusses the unusual 

 attacks by C. beticola on sugar beets in 1915 and the effects thereof on beet 

 products, some of which were considerably altered in their proportions, as 

 shown by comparative tables for 1915 and some earlier years. 



A disease of sugar beets, A. Morvillez {Jour. Fabric. Sucr., 56 {1915), No. 

 11, pp. 1, 2). — The author considers the losses to the sugar-beet industry in 

 1915 as due primarily and largely to insufficient nutrition. 



Sugar beet disease, P. Bebthaui^t {Jour. Agr. Prat., n. ser., 29 {1916), No. 

 2, pp. S5, 36). — The author, discussing the above contributions by himself. Sail- 

 lard, and Morvillez, considers the attack by Cercospora beticola and the asso- 

 ciated abnormal chlorosis as closely related phenomena, the latter being prob- 

 ably dependent upon the former. 



Internal action of chemicals on resistance of tomatoes to leaf diseases, 

 J. B. S. Norton {Maryland Sta. Bui. 192 {1916), pp. 17-30, fig. i).— After re- 

 viewing the literature describing the effect of soil applications, direct injection, 

 and the use of serums and toxins for the prevention of plant diseases, the 

 author describes some experiments carried on in 1912 and 1913, in which 

 about 50 chemicals were employed to determine their effect on infection of 

 tomatoes by Septoria lycopersici and Cladosporium fulvum. 



The plants were grown in paraffin-covered paper pots suspended in glass 

 tumblers above solutions of different proportions of the various chemicals, 

 their roots extending downward to the solution of the chemical, which did 

 not come in contact with the soil. 



