DISEASES OP^ PLANTS. 951 



practically pnitccttHl tliciu fidin tlie disease. Trees not sjirayed lost almost the 

 entire croji. 



Peach rot (OklalKiiiia tita. Ri>t. JDOS, py. 78, 79). — Directions are given for 

 the prevention of peach rot bj- the use of applications of Bordeaux mixture or 

 au.uioiiiMcal copp(>r carl)onate. 



Studies in cacao disease, J. H. Hart {I'roc. Agr. Sac. Trinidnd and Tohayo, 

 S (11)08), Xo. 11. pp. 303-508). — The author gives an account of an injury 

 caused to cacao by the fungus Diplodia oicaoicoht. This fungus, it is said, 

 causes the brown rot of the pod and die baclv of the branches, and also affects 

 the roots of the trees. Atteuaon to plantations, pruning out and burning 

 affected portions, and cultivation resulting in an active growth of the trees 

 are recommended as jireveutive nuvisures. 



Inoculation experiments ivith Peridermi'i.ni strobi from Pinus monticola, 

 F. W. Xkger (XdlKiir. ZLschr. Forst ii. Laiidic, G iltlOH), \o. Li, p. 605). — In 

 order to determine the alternate host plant for the peridermium stage of Prii- 

 dcrmiiim strohi from I'iiius monticola, the author planted in TDO.") a number of 

 currant bushes among a vigorous stand oi IS-year-old trees of P. monticola. 

 The si>ecies of Kibes jilanted were R. fianguincnm, R. alpiniun, R. nih im, 

 R. avrcum, and R. grotamlaria. 



From 10<)5 to 1907 there was no trace of the uredo or teleuto forms on any of 

 the plants. In 1908 the infection made its ap!)earauce but was found only on 

 R. sangiiinciim. The investigations indicate that R. alpinnm is not the alter- 

 nate host for the peridermium of the si)ecies that occurs on P. monticola, 

 but probably is the alternate host for the forms occurring on the stone pine 

 (/'. ccmbra). 



The use of copper fungicides, K. von Tubeuf (Xaturw. Ztschr. Forst u. 

 Landw., 6 (1908), Xos. 3. pp. 200-203, figs. 3; //, pp. 229-23o, figs. 3; 5, pp. 

 281i-288, figs. 2). — The action of various copper fungicides is described and notes 

 given on their successful use in combating a number of plant diseases, par- 

 ticularly those of fruits, grapes, and potatoes. The fungi and the effect on 

 their host plants are described, after which directions are given for the prepa- 

 ration and use of copper sulphate soUitions, Bordeaux mixture, soda Bor- 

 deaux, etc. 



Sulphur as a pest remedy, C. F. Jtjritz (Agr. Jour. Cape Good Hope, 33 

 (l!)08), Xo. 6, pp. 719-730. figs. .3). — On acconnt of numerous inquiries regarding 

 the kind of sulphur suitable for combating powdery mildew of grapes, sheep 

 scab, and scale in orchards, the author has made a study of the different forms 

 of sulphur found in commercial use to determine their value as remedies for 

 these troubles. 



As the form of sulphur is of most importance in combating junvdery mildew, 

 this phase formed the principal portion of the investigation. The action of 

 sul|)hur when used as a fungicide is said to be due to the destructive effect on 

 the mycelium and sjiores of tlie fumes whidi are given off when the weather is 

 sufficiently warm. In order to have the proper effect it lias been found that the 

 sulphur must be evenly distributed and must be in actual contact with all the 

 diseased i)arts of the vine. Studies were made of the fineness, i>urity, diimpness, 

 and presence of free sulphuric acid in the different samples, and it was found 

 that sulphur, wlwtlier ground or in the form known as t1owei-s of sulphur, to be 

 effectual for destroying mildew must possess the following physi<-al and chem- 

 ical proiuMties : Fineness, uniformity of fineness, absence of clogging tendency, 

 purity, freedom from moisture, and freedom from hygroscopic substances. In 

 testing the comparative adaptability of the different forms, it was found that 

 fineness is not the only consideration, as a large proitortion of the sulphur 



