DISEASES OF PLANTS. 269 



of the ground and results later in a peculiar branching or clustering of the leaves. 

 This clustering, which is possibly secondary, is so conspicuous that it affords a sufla- 

 cient means for the detection of a large percentage of the affected plants. 



The disease has been under observation since 1900, and from the results obtained 

 is apparently disseminated with the seed tubers. Attention was first called to it by 

 the widespread occurrence through seed tubers that had been sent out from the 

 station. Subsequent investigations seemed to prove that it spread from the station 

 as a center, and methods of prevention were investigated. Tubers were treated with 

 a solution of formalin before planting, and in 1902 there was practically no evidence 

 of the rosette disease in the leaves of growing plants in the rows treated with formalin. 

 Where the seed tubers had been given a treatment with corrosive sublimate previous 

 to planting, there was no indication of immunity from disease.- This method of treat- 

 ment has been continued, and based upon 2 seasons' work the conclusion is drawn 

 that formalin treatment will prevent Rhizoctonia disease to a very marked extent. 



The author calls attention to the extreme diversity in injury among several 

 varieties of potatoes grown at the station, and states that an average of from 6 to 20 

 per cent loss was due to this disease. For the practical prevention of the rosette 

 disease, soaking the seed tubers for 2 hours in a solution of formalin composed of 0.5 

 pt. formalin to 15 gal. water is recommended. The bulletin concludes with citations 

 to literature regarding Rhizoctonia diseases. 



Remedies for the root disease of sugar cane {Agr. N'eivs [Barbados], ,? {1903), 

 No. 29, p. 162). — The writer suggests preventive measures for combating the root 

 disease of cane. The means suggested consist of selection of resistant varieties, plant- 

 ing healthy canes, careful cultivation and thorough drainage, rotation of crojjs, and 

 the removal of diseased plants when discovered to prevent the fungus spreading to 

 healthy ones. The diseased areas may be isolated by digging trenches a foot to 18 

 in. deep about the diseased plants, care being taken that the infested soil should not 

 be thrown toward the healthy plants. In no case should the diseased canes be 

 allowed to rattoon. The root disease, which is due to Marasmius, is said to have 

 caused considerable loss to the planters of the West Indies during the past season. 



Pests of garden veg-etables, M. C. Cooke {Jour. Roy. Hart. Soc. \_London'], 27 

 {1903), No. 4, pp. SOl-831, pis. 3, fig. 1). — Descriptions are given of a large number of 

 the more common fungus diseases which attack garden vegetables, and, so far as 

 known, methods are suggested for the prevention of their attack. 



A new disease of beans, A. Maige {BuI. Agr. Algerie et Tunisie, 9 {1903), No. 14, 

 p. 334). — A brief description is given of a disease of green beans which has proved 

 very destructive in gardens during the past season. This disease is characterized by 

 a development on the leaves of greenish-yellow spots which, extending little by little, 

 finally involve the entire leaf. The fungus causing this disease has jiot been defi- 

 nitely determined, but reasoning from analogy of other diseases the author believes 

 that this disease could be held in check by the xise of standard fungicides. 



The parasitism and development of Sclerotium cepivorum on onions, P. 

 VoGLiNO {Staz. Spcr. Agr. Itul., 36 {1903), No. 2, pp. 8^-106, ph. 2, fig. 1). — A study 

 was made of the cause of the almost total loss of the onion crop in jiarts of Italy, and 

 the results of investigations are given. The disease has been under observation since 

 1897, the last serious outbreak occurring in 1901 followed by a rare occurrence in 

 1902. The cause of the disease is attributed to l^rlcrotkun cepivorum, which develops 

 a conidial form, that has formerly been recognized as Spltacelia allii, upon the dead 

 leaves and bulbs. The biology of the fungus is described and its parasitism aflirmed. 

 During hot weather the fungus develops with great rapidity in moist rich soils, par- 

 ticularly in those containing a large amount of humus. The only suggested means 

 for i)reventing this disease is the aljandonment of onion culture in infected soils. 



Notes on a disease of black salsify, R. AnEKnoLD {Arh. K. Gesumllieilsande, 

 Biol. Aht., 3 {1903), No. 4, pp. 439, 440,fig.l). — The author describes a disease of black 



