544 EXPERIMENT STATION RECOED. I Vol. 36 



Peanut mosaic, J. A. McClintock {Science, n. ser., 45 {1917), No. 1150, pp. 

 47, 4S). — The author reports having observed in a peanut field a plant one shoot 

 of which bore mottled leaves. This plant was transferred to a greenhouse, and 

 at the same time mature pods from it were planted to determine whether the 

 mosaic would be transmitted, but thus far there is no indication that the trouble 

 is carried by the seed. Attempts to produce mosaic by inoculation, as well as 

 other tests to determine its infectious nature, have given negative results. 



Fungus parasites of the pigeon pea, E. Rangel {Lavoura; Bol. Soc. Nac. 

 Agr. [Brazil], 18 {1914), No. 1-4, pp. 5-18, pis. 3).— This information, which 

 has been noted previously from another source (E. S. R., 34, p. 52), is here given 

 in both Portuguese and French. 



A contribution to our knowledge of silver scurf (Spondylocladium atro- 

 Tirens) of the white potato, J. J. Taubenhaus {Mem. N. Y. Bot. Gard., 6 

 {1916), pp. 549-560, pis. 3). — It is claimed that S. atrovirens, which is carried 

 by seed or soil, is the cause of the disease of white potato known as silver scurf. 

 This fungus is not causally connected with PhcUomyees sclerottophorus, which 

 appears to be a saprophyte or very weak parasite. It is stated that the genus 

 Phellomyces is not valid, the fungus really belonging to Colletotrichum, and P. 

 sclerotiophorus being identical with C. solanicolum and Vertnicularia atramerir 

 taria. It has accordingly been designated as C. atramentarium. 



The sweet potato " soil rot " or " pox," a slime mold disease, J. A. Elliott 

 {Delaware Sta. Bui. II4 {1916), pp. 2-25, figs. 22). — For .several years work has 

 been in progress on the cause and means of control of a disease of sweet potato 

 known as soil rot or pox. The author, in the present publication, gives an ac- 

 count of laboratory studies and field observations of this disease, w^hich he 

 reports is due to a slime mold and not to Aorocystis batatce, as previously 

 claimed (E. S. R., 2, p. 416). The organism causing the disease is described 

 under the name Cystospora batata n. g. and sp., and its life history and cytology 

 are reported at length. 



The sweet potato " soil rot " or " pox " organism, J. A. Elliott {Science, n. 

 ser., 44 {1916), No. II42, pp. 709, 710). — A preliminary account is given of the 

 Bweet potato soil rot or pox (see above). 



Tree wounds and diseases, their prevention and treatment, A. D. Websteb 

 {London: Williams & Norgate, 19 JO, pp. XX +215, pis. 32, figs. 9).— This book 

 deals in a general way with the treatment of tree wounds and diseases, the 

 information being based on the author's practical work and observation. The 

 author discusses the management of decaying trees, treatment of hollow trunks, 

 supporting heavy and diseased branches, treatment of injuries from various 

 causes, such as the adverse influence of soil or atmosphere, fungi, insects, etc., 

 the prevention of diseases, and accidents and diseases to which trees are liable, 

 A special chapter is given on fruit trees and their enemies. 



Sun scald of fruit trees, a type of winter injury, A. J. Mix {New York Cor- 

 nell Sta. Bui. 382 {1916), pp. 235-284, pis. 2, figs. 2).— A description is given of 

 the winter injury to fruit trees commonly known as sun scald, in which the 

 sun-exposed side of the trunk is affected. Two other types of injury somewhat 

 related to sun scald are crotch injury and crown injury, or crown rot, both of 

 which are discussed in connection with sun scald. In the author's experiments, 

 artificial freezing and thawing at various temperatures were resorted to, their 

 effect on the cambium being noted. 



Sun scald injury is considered due to direct freezing to death of tissues 

 through an increased tenderness of the tissue on the sunny side of the trunk in 

 late winter or through a rapid temperature fall which causes the killing of the 

 tissues on the sunny side of the tree at a higher temperature. Both of these 



