DISEASES OF PLANTS. 441 



Report on forestry. Wehlburg {Jnarh. Dcpi. Lnmlb. Nijv. en Hnndel Xedcr- 

 htnd. Inilii', r.U-i, ;>/>. 2'.Ki-.]0G). — A progress report on forest administration in 

 the Dutch East Indies, including information relative to alterations of forest 

 areas, cultural operations, forest protection, exploitation, yields in major and 

 minor forest products, revenues, expenditures, etc. 



DISEASES OF PLANTS. 



Report of the division of botany, II. T. Gtissow and J. W. Eastiiam (C'on- 

 udn E.rpt. Faniiti Ri)ts. 1913, pp. JiS0-.'i92). — An account is given of some of the 

 investigations which have been pursued during the year of the report, the work 

 covering a study of the storage rots of potatoes, experiments with Rhizoctonia 

 disease of potatoes, potato scab experiments, ergot, and storage spot of the 

 apple. 



Under the heading of storage rots the author describes all the troubles due 

 to various organisms, and calls attention to the advisability of proper storage 

 and the removal and destruction of diseased tubers whenever foimd. 



In the experiment for the control of the Rhizoctonia disease, tubers were 

 l)lanted in a tract of land that had pre\'iously been badly infected with the 

 fungus. One-half of the area was limed and the other half left untreated. The 

 seed tubers were given various treatments, such as soaking in corrosive sub- 

 limate solution, dipping in glycerin and rolling in sulphur, and soaking in lime- 

 sulphur solution. Examination of the crop showed no constant differences so 

 far as the treatment was concerned, but the variety Carman No. 1 was almost 

 entirely free from Rhizoctonia on the tubers. 



The experiments with potato scab control included treatments with chlorid 

 of lime, corrosive sublimate, lime-sulphur solution, .sulphur, and sawdust. Saw- 

 dust has been claimed to be valuable for the control of this trouble, but proved 

 to be of no benefit. The lime sulphur reduced scab more than any of the other 

 treatments, although more than one-third of the tubers showed the presence of 

 some scab. 



The storage spot of api)le was first noticed on Gravenstein apples in which 

 spots varying from 0.3 mm. to 5 mm. in diameter were observed. These were 

 depressed, brown in color, with dark centers, and in many cases appeared to be 

 about a lenticel. The spots were usually less abundant on the side of the apple 

 exposed to the sun. Cultures were made of diseased tissue and attempts made 

 to determine the cause, but without evident success. The authors state that 

 while the cause has not yet been demou.strated, it seems to be of a nonparasitic 

 and external nature and to have much in common with the so-called Jonathan 

 spot, which is suspected to be due to use of arsenate of lead as an insecticide. 



Report from the branch laboratory of the division of botany, W. A. 

 McCuBBiN (Canada Expt. Farms Rpts. 1013, pp. Ji97. 498). — An account is given 

 of the investigations being conducted at the branch laboratory at St. Catharines, 

 Ontario, the work reported being mostly that of a study of peach cankers, cur- 

 rant diseases, yellows, little peach, raspberry cane blight, etc. 



The author reports the occurrence of Pyropolyponis ribis in large numbers 

 ou currants, and although a number of fungicides were tested none of them 

 seemed to have proved effective in destroying the fungus. 



The raspberry cane blight, which was rather prevalent and destructive in 

 some parts of the district, was studied and experiments begun on the control 

 of the disease by spraying. 



[Plant diseases in Mauritius], F. A. Stockdale Qn Suminart/ of Invesiiga- 

 iions of Fungus Diseases and Insect Pests Made During the Six Months Ended 



