540 EXPERIMENT STATION EECOKD. 



Report by the botanist, W. Small {Ann. Rpt. Dept. Agr. Uganda, 191 Jf, pp. 

 59-62). — This report deals mainly with plant diseases. 



The successful use of the sprays noted on page 545 for leaf disease of coffee 

 is reported, the results from the use of other sprays being less satisfactory. 

 The experiments for the purpose of testing the supposed identity of Hemileia 

 vastatri.v with the Hemileia disease occurring commonly on native coffee gave 

 negative results and are to be repeated. 



Hymcnocho'te noxia, causing root disease of coffee, has not done extensive 

 damage. Sooty mold (Capnodivm brasilicn-sc) yields to treatment destroying 

 the insects in connection with which it commonly occurs. 



The die-back of coffee is thought to be connected with abnormal conditions, but 

 it is considered as somewhat obscure with regard to the manner of its causa- 

 tion. Further studies in this connection are in progress. 



Hevea, while remarkably free from fungus diseases, was attacked by a 

 brown root disease in one place. A disease characterized by gummy exudations 

 and bark discoloration was not'?d in connection with Plnjtophthora fnberi. A 

 few cases of die-back of Hevea require further examination, Glocosporium al- 

 horuhrum, PhijUosticta ramicola, and Thyridarin tarda being noted in this con- 

 nection. 



Cacao stems showed the presence of T. tarda, Mcgalonectria psevdotrichia, 

 and Ncctria spp., and on the pools were f(umd P. fabcri. T. tarda, and CoUeto- 

 trirhnm incarmitiiw. but it is not known which of these may cause injury. 



The composition of Bordeaux mixture and its soluble copper content, V. 

 Vebmorel and E. Dantony {Prog. Agr. ct Tit. {Ed. VEst-Ccntre), SG {1915), 

 No. 19, pp. Ji.38-4.'i2). — This is a further statement regarding studies previously 

 noted (E. S. R., 32, p. 544). 



It appears that acid Bordeaux mixture contains basic sulphates of copper, 

 but no hydrates thereof. The alkaline mixtures, as freshly made in the .same 

 proportions of copper sulphate and of linio. may present differ<'nces as regards 

 composition, showing a blue color and containing a large proportion of hydrates, 

 or a green color, containing abundant basic sulphates or intermediate types. 

 The mixture as used, however, generally contains a sufficient proportion of the 

 dissolved copi)er to check the development of mildew. 



Under the action of carbon dioxid, the alkaline mixture yields at first less 

 copper than does the acid solution, but after a certain time, especially in case 

 of the lilue preparation, it yields a considerable amount of soluble copper. If 

 the action of the carbon dioxid is sufficiently prolonged, either the acid or the 

 alkaline mixture shows the formation of the basic carbonate of copper. 



It is considered as probable that the acid and the alkaline mixture may have 

 about equal values as fungicides. 



The after effect of sulphur treatment on soil, C. D. Sherbakoff {Phyto- 

 pathologii, 5 {1915), No. 4. PP- 219-222, figs. 3). — In a previous publication 

 (E. S. R., 32, p. 146), the author gives an account of investigations on the 

 control of potato scab by the application of sulphur. In the present paper, 

 the effect of the sulphur treatment on the growth of subsequent crops, par- 

 ticularly clover, is shown. 



Where sulphur was applied at the rate of 000 lbs. per acre in 1012 and 1013, 

 there was a noticeably poorer stand of clover than on adjacent plats ; where 

 It was applied at this rate in combination with lime and additional fertilizers, 

 a less injurious effect was shown ; and wliere applied at a greater ratio, no 

 growth of clover at all was observed. The treatments in which sulphur was 

 applied at the rate of 450 lbs. per acre, either alone or in combination, showed 

 on injurious effect on clover only in those parts of the field which were poor in 



