1919] DISEASES OF PLANTS. 347 



The fungi are said to overwinter on dead leaves which escape decay, and 

 the source of new infection is furnished by ascospores produced in the spring. 

 Efforts to exclude the disease from alfalfa fields by the use of seeds that have 

 been given surface sterilization were without success, and it is believed that 

 tlie fungus is not carried on the surface of the seed and probably not with 

 the seed at all. 



[Work in plant genesis], A. F. Blakeslee (Carnegie Inst. Washington Year 

 Book, 17 {1918), pp. 114-116). — Besides other more or less related matters, re- 

 ports are made on the apparent immunity of adzuki beans to anthracnose in 

 connection with their susceptibility to bean mosaic. 



Chlorotic corn, W. H. Davis (Proc. Iowa Acad. ScL, 24 {1911), pp. 459, 460). — 

 Observations on chlorotic progeny of seeds from an ear of yellow dent corn 

 and on corn leaves pierced wath needles which have been used to wound 

 chlorotic leaves appear to show that corn embryos may be chlorotic, that 

 chlorosis in corn is probably not transferable by contact or with the sap by 

 way of wounds, and that corn plants which are entirely chlorotic will not 

 mature. 



The influence of drought and of Alternaria on potato, J. Sordina {Prog. 

 Agr. et Tit. {Ed. VEst-Centrc), 39 {1918), :\o. 6, pp. 131-134, figs. 2).— The 

 author notes, in connection with somewhat exceptional weather in exposed sit- 

 uations in the island of Corfu, the appearance of a potato disease apparently 

 connected with A. solani which is discussed in relation with treatment. Two 

 sprayings employing Bordeaux mixture at 1 per cent and 0.5 per cent, respec- 

 tively, are considered as sufficient. 



The eradication of yellow stripe of sugar cane (Porto Rico Dept. Agr. Sta. 

 Circ. 14 (1918), Spanish Ed., pp. 8, i)Js. 3). — This circular includes an account 

 hy E. D. Colon of data and deductions regarding the yellow stripe disease of 

 sugar cane noted by Stevenson (E. S. R., 38, pp. 851, 852), which is now 

 causing much injury to the siigar industry in parts of Porto Rico. The disease 

 is not curable by treatment or by improvement of cultural conditions. Varieties 

 differ as regards susceptibility to the disease, which appears to be hereditary. 

 The boundaries of the areas affected are being extended. 



The second part of this publication, by F. S. Earle, deals with matters relating 

 to control of the disease, which is said to be incurable as regards individual 

 plants. The employment of strictly sound material for propagation, inspection 

 of growing crops at frequent intervals, and eradication of all but unquestionably 

 sound canes are relied upon to relieve the situation, which is declared to be 

 critical. 



Blister canker of apple trees, a physiological and chemical study, D. H. 

 Rose (Bot. Gas., 67 (1919), No. 2, irp. 105-146, figs. 10).— In a continuation of 

 work previously noted (E. S. R., 34, p. 13G), employing in this latter phase also 

 the simplified Bunzel apparatus previously described, with the addition of a 

 study of catalase activity with microchemical and macrochemical analysis of 

 both healthy and diseased apple tree bark, the author claims to have found 

 tliat apple bark attacked by Nummnlaria discreta approximately doubles the 

 oxidation of pyrogallol, pyrocatechin, guaiacol, and benzidin, as compared with 

 that occurring in healthy bark. Tlie gradual slowing down of oxidation in the 

 Bunzel apparatus is due, in part at least, to increasing H-ion concentration 

 brought about by the oxidation process itself, the equilil)rium reached in the 

 apparatus being supposetlly a false one, readily upset by addition of fresh oxi- 

 dase reagent or plant material. The oxidase may be a catalytic agent. H-ion 

 concentration is less in diseased than in healthy bark. Temperature and dura- 

 tion of drying have an effect on the acidity and the oxidase activity of both 

 healthy and diseased bark. When oxidase is precipitated in two fractions the 



