No. 2, December, 1921] PATHOLOGY 107 



687. Melhus, I. E. Bremia on hothouse lettuce. [Abstract.] Phytopathology 11: 

 54. 1921. 



C88. MifcoB, Emile. Note preliminaire sur les principales maladies cryptogamiques ob- 

 servees au Maroc. [Preliminary note on the principal fungus diseases of Morocco.] Bull. 

 Soc. Path. Y6g. France 8: 37-40. 1921. — A brief list, with notes, is presented of the common 

 parasites of the principal farm crops. — C. L. Shear. 



689. Millard, W. A. Common scab of potatoes. Jour. Ministry Agric. Great Britain 

 28: 49-53. 2 fig. 1921. — Experiments, details as yet unpublished, show that scab in England, 

 as in America, is caused by Actinomyces scabies. Planting diseased "seed" has produced only 

 a very slight increase in scab. Control has been obtained by plowing under green crops. — 

 C. W. Bennett. 



690. MoLLTARD, M. La galle de I'AuIax minor Hartig. [The gall of Aulax minor Hartig.] 

 Rev. Gen. Bot. 33 : 273-294. PI. 46-53, fig. 1-9. 1921.— The 2 types of galls caused by Aulax 

 minor on Papaver rhaeas are described and their method of development traced. The galls 

 differ from those produced on Papaver dubium by Aulax papaveris. — /. C. Oilman. 



691. Poole, R. F. Recent studies on bacteriosis of celery. [Abstract.] Phytopathology 

 11:55. 1921. 



692. Richards, B. L. A dry rot of sugar-beet caused by Corticium vagum. [Abstract.] 

 Phytopathology 11: 48. 1921. 



693. Rivera, Vincenzo. Sopra 1' azione del Fomes fulvus (Scop.) Fries sul mandorlo. 

 [The action of Fomes fulvus (Scop.) Fries upon Amygdalus.] Staz. Sper. Agrarie Ital. 54: 

 114-118. 1921. — The fungus appears to be a true parasite capable of growing for several 

 years in the host without showing a tendency to form fruiting bodies, but capable instead of 

 forming in the cambium layer a thick, tough mycelial mat. A general, premature ageing and 

 a shortening of the internodes in the new branches are the first signs of the disease. It is 

 only when the tree is in the final stages of alteration that the parasite gives rise to fruiting 

 bodies. This form of the disease, which is apparently transmitted by pruning implements 

 and which the author characterizes as the "biologic" form, is to be distinguished from the 

 "chemico-biologic" form, which is responsible for the death within a short time from planting 

 of large numbers of replacement plantings. The latter form of the disease, characterized by 

 a complete lack of mycelial development either in the roots or branches, should be ascribed to 

 an intoxication by some product arising from the final decomposition of the remains of the old 

 infected tree under the saprophytic action of Fomes fulvus. Sterilization of pruning imple- 

 ments is recommended as the only rational measure for combatting tha disease that in some 

 regions is very destructive.^^. Bonazzi. 



694. Rosen, H. R. A bacterial root and stalk rot of field com. [Abstract.] Phytopath- 

 ology 11: 32-33. 1921. 



695. Salmon, E. S. Hop-"mould" and its control, I. Jour. Ministry Agric. Great 

 Britain 28: 150-157. 10 fiig. 1921. — Mildew, Sphacrotheca humuli, is reported as destructive 

 to the leaf, "burr," and hop-cone of the hop plant. Dusting with flowers of sulphur, cleaning 

 away trash, and removing infected parts from the vines are discussed as control measures. — 

 C. W. Bennett. 



696. Spierenburg, DiNA. Eenonbekendeziekteindeiepen. [An unknown disease of elm.] 

 Tijdschr. Plantenz. 27: 53-60. PI. 3. 1921. — This disease, which was seen in various parts of 

 Netherland for the 1st time during the year 1920 and which seems to be becoming of very 

 great importance, manifests itself by a more or less rapid wilting and dying of the tops of the 

 trees or of single branches, while the whole tree takes on a sickly appearance as if it were suffer- 

 ing from lack of food and water. The branches and stem in cross section show small dark 



