DISEASES OF PLANTS. 45 



author presents a study of the causes of a general rotting of root crops 

 (mangels and ruta-bagas) on Danish farms during the winter of 1908-9. 



Fungus diseases of the apple, Edna F. McCormack {Ann. Rpt. State Ent. 

 Ind., 3 (1909-10), pp. 128-165, figs. 29). — The author describes the symptoms 

 of the common diseases of the apple in Indiana, and gives the measures to be 

 used in combating them. 



Observations on the susceptibility of different kinds of cherries to the 

 Botrytis fungus (Sclerotinia cinerea), G. KocK (Ztschr. Landw. Versuchsic. 

 Osterr., 13 {1910), No. 11, pp. 889, 890).— It is claimed that the apparent im- 

 munity of certain A'arieties of cherries to the attacli of this fungus is due to the 

 fact that their time of blossoming for a given locality does not coincide with 

 the weather conditions favorable for the propagation of this disease, while 

 other varieties which are apparently susceptible have their blooming period 

 coincident with the weather conditions suitable for infection by the Botrytis 

 rot {8. cinerea), and therefore are often severely attacked by the fungus. 



Contribution to the biology of the grape mildew, J. Laurent {Rev. ScL 

 [Paris], Jf9 {1911), I, No. 9, pp. 267-272).— The author discusses the variation 

 in virulence of the mildew and the relative susceptibility and immunity of 

 certain varieties of the grai)e to the disease. Attention is again called to the 

 results of experiments (E. S. R., 24, p. G50) in which the degree of sap con- 

 centration seems to indicate the immunity to the disease which a given variety 

 of grapes may possess, the higher the molecular concentration the greater 

 being the resistance. 



[Decree concerning the exportation of diseased fruit trees from Holland] 

 (Bui. Mens. Off. Renseig. Agr. [Paris], 10 {1911), No. 1, pp. 39-//-'/).— The text 

 is given of a decree issued in Holland in 1909 concerning the inspection of all 

 fruit trees offered for expoi't. A certificate is required showing the nature of 

 the shipment, where grown, the point of distribution, and a statement from the 

 state entomologist and phytopathologist of Holland that the plants have been 

 inspected and found free from the San Jose scale, peach yellows, rosette, or 

 other i>ests liable to dissemination on nursery stoclf. 



Brown root disease, T. Fetch {Circs, and Agr. Jour. Roy. Bot. Gard. Cey- 

 lon, 5 {1910), No. 6, pp. 47-54, pls. 3). — The symptoms, cause, and methods 

 of infection of this disease are given. It attacks many kinds of plants, such 

 as Hevea, cacao, tea, dadap, Castilla, Caravonica cotton, camphor, and Briin- 

 felsia amcricana, and is characterized by an encrustation of the roots, espe- 

 cially the tap root, with a mass of sand, earth, and small stones to a thickness 

 of 3 to 4 mm. ; this crust, as a rule, extends up the stem for several inches. 



Recently the fungus concerned has been certainly identified as HymenoolKete 

 noxia by its fructifications, which form a thin, dark brown crust on the base 

 of the stems. As the fructifications of this fungus appear only on stems or 

 stumps dead for a long time, the spread of the disease from one living plant 

 to the next is due to the mycelium spreading from root to root of adjacent 

 plants where the roots are in contact. 



In Ceylon the disease attacks cacao and spreads from it to the Hevea trees 

 which have been interplanted with cacao. The remedial treatment consists 

 of the removal and burning of the dead trees and their roots, and in case of 

 young Hevea planted on old cacao land all cacao stumps should be dug out 

 at once. 



A similar jungle disease attributed to H. rigidula and found on several species 

 of trees is also discussed, and the peculiar, honeycomb-like character of the 

 diseased wood is figui'ed. 



The Gloeosporium rot of bananas and a Phyllosticta leaf spot of ivy, R. 

 Laxjbert (Gartenflora, 59 {1910), No. 19, pp. 409-415, pi. 1, figs. 2 ) .—Attention 



