DISEASES OF PLANTS. 849 



blight (Ewobasidium rc.rans), bninissuiv {HoroHitluvm thca'), and red rust 

 {Ccphalciiros vircsccns). In addition a number of other species of funsi that 

 are found upon the leaves are described, but they are said to be seldom serious 

 in their attack. 



Among the most destructive diseases of the stem and roots of the trees are the 

 thread blight (Siilbum iHinion), canker (Nectria ditissinia), a stem disease 

 (Massaria theicola), horse-hair blight (Marasmius sarmentosus), root rots 

 {RoseUiiiia radiciperda and Trametes them), nematodes, and phanerogamic 

 parasites. 



A root disease of Para rubber trees, W. J. C4allagher (.1.^//-. liuJ. Stniits 

 and Fed. Mahui States, 7 (JDOS), Xo. 11, pp. r,15~i)22, dfjni. /).— The author re- 

 ports the rather conuuon occurrence throughout the Malay Peninsula of a 

 fungus which attacks the roots of the Para rubber trees {Hevea hrasiiliensis). 

 The disease is seldom distributed over an entire estate, but is confined to limited 

 areas which appear to serve as centers for its distribution. 



The presence of the disease is not usually noticed until the tree is dead. The 

 first symptoms are observed in the leaves becoming brown about the edges, and 

 the entire leaf soon loses its natural color. Little or no latex will flow from 

 wounds in the stem, and later the trees are blown down. This is apiiarently due 

 to the desti'uction of the lateral roots of the trees. So far as the author has 

 observed, the attack seems to be in the more superficial lateral roots, and on 

 different occasions he has traced the mycelia of the fungus along the lateral 

 roots to decaying jungle stumps. 



Thus far, owing to a lack of fruiting bodies, the identification of the fungus 

 has been impossible, but it is believed to be one of the higher fungi similar to 

 the bracket fungi. 



As remedial measures, the author suggests trenching about trees and destroy- 

 ing the fungus by exposure to the sun and the application of lime. 



Recent investig-ations on the disease of fir trees caused by Phoma abietina, 

 E. Mek (Bui. Soc. Sci. Xancy, 3. ser.. 9 (1008), Xo. 2. pp. 10',-l'f-',).—A discussion 

 is given of the disease of firs due to P. abictiiHi. The author protests against 

 the name rust or reddening of firs, as he states that the reddish-brown color is 

 due simply to the oxidation of the tannins in the leaves followed by their 

 destruction by the fungus. 



While there has doubtless been considerable loss in some regions due to the 

 defoliation caused by this fungus, the author thinks it will seldom prove of a 

 very serious nature. Where the fungus is abundant, it is reconunanded that the 

 lower branches be cut from the trees and burned. This will not only improve 

 the vigor of the trees, but through the removal of leaves weakened by lack of 

 illumination, etc., the spread of the fungus will be checked. 



The leaf rust of spruce, P. Dei-forge (Bui. Soc. Cent. Forest. BeJg., 15 

 (lOnS), \o. 9; noted in Rn: den. Agrnn.,n. ser., 3 (1908), .Vo. 10. pp. .',2.'i-.',21).— 

 A description is given of a leaf rust of spruce due to the fungus Clnijsomij.ra 

 abietis, which has proved rather destructive in a number of localities in Europe 

 during the past season. 



The mici'oscopical character of the fungus and its effect on the plants are 

 described, the injurious action being apjiarently due to the consumption by the 

 fungus of the elaborated material in the leaves and the diminution of their 

 assimilating surface. I^ater the fungus causes a premature falling of the leaves, 

 the amount of injury varying with the intensity of the attack, and in different 

 years, regions, etc. 



As means f(U" i)reventiug the si)read of the disease, the author recommends 

 thinning out the trees, so that there will be a better circulation of air, thus re- 



