48 EXPERIMENT STATION RECORD. 



while in winter storage. Ttie fungus is incapable of infecting any other part 

 of the potato plant than the tuber, and it can not invade the tuber until it is 

 practically mature and then only through wounds. During the winter season 

 the tubers are more rapidly destroyed by this di^y rot than at harvest time. 

 The possible loss due to this trouble may be greatly reduced by treatment with 

 fungicides. 



A bibliography of the subject is given. 



A dry rot of the Irish potato tuber, E. M. Wixcox and G. K. K. Link 

 {Nebraska Sta. Bui. 1S4, pp. 8, pis. 3, fig. 1). — This is a popular edition of the 

 above. 



A biochemical study of the curly top of sug-ar beets, H. H. Bunzel (!7. 8. 

 Dept. Aur., Bur. Plant Indus. Bui 277, pp. 28). — In this paper the author sum- 

 marizes the results of experiments on the application of the manometric method 

 to a study of the curly top of sugar beets, a preliminary note of which has been 

 given elsewhere (E. S. R., 26, p. 848). This trouble has been attributed to 

 many causes, among them atmospheric conditions, micro-organisms, insects, 

 irrigation, etc. 



In 1911 the author carried on experiments to determine the oxidase content 

 of healthy and diseased sugar beets grown in the greenhouse. The results 

 seemed to be quite conclusive in showing differences in the oxidase content of 

 the healthy and diseased sugar beets, and later the work was carried on in 

 the field, where the greenhouse results were corroborated. 



The leaves of the curly-top plants were found to have an oxidase content 2 

 or 3 times as great as the healthy and normally developed ones. No marked 

 differences could be detected between the roots of the two kinds of plants, but 

 an abnormally high oxidase content of the leaves was found in all plants the 

 growth of which had been retarded from any cause. 



The general conclusion is drawn from the observations that an abnormal 

 retardation of growth in sugar beet plants is accompanied by an increase in the 

 concenti-ation of oxidases in the leaves, or a change in the juice of the latter 

 by which the pyrogallol oxidizing oxidase becomes more active. 



The contrdl of the sug'ar beet leaf spot, Venus W. Pool and M. B. McKay 

 (U. 8. Dept. A<ffr., Bur. Plant Indus. Circ. 121, pp. 13-17). — An investigation of 

 the leaf spot of the sugar beet, due to Cercospora heticola, has been caiTied on 

 in cooperation with the American Beet-Sugar Company, and although the study 

 is as yet incomplete, a brief accoimt is given of some of the results, which in- 

 dicate possible methods of control. 



The fungus was found to live through the winter on the old beet tops of the 

 preceding season, and the results thus far obtained indicate that the organism 

 is unable to survive a passage through the alimentary tract of cattle, sheep, 

 and pigs. As it is impossible to prevent some waste in feeding beet tops and 

 subsequent infestation, it is recommended for the complete control of the disease 

 that the beet tops be removed from the fields while still green and made into 

 silage. The fungus is killed when the beet tops are siloed. 



A new leaf spot of cucumbers in Saxony, A. Naumann (Ztschr. Obst. u. 

 Garteiibau, 1912, A'o. 7, p. 99; ahs. in Ztschr. Landw. Versuchsw. Osterr., 15 

 {1912), No. 12, p. 1305; Bot. Centbl., 122 (1913), No. 13, p. 287).— A new 

 disease of cucumbers, claimed to have been introduced on English seed, is 

 described. It is said that steeping the seed in 0.5 per cent solution of formalde- 

 hyde for 15 minutes, or in 0.5 per cent copper sulphate for 20 hours with a wash 

 of lime water afterwards, gives efficient protection. 



Some diseases of garden plants and frost injuries of apples, A. Naumann 

 (Jahresber. Ver. Angew. Bot., 9 (1911), pp. 198-217, figs. 9).— The author gives 

 an account of a spreading leaf gall of Azalea indica which was stopped by the 



