DISEASES OF PLANTS. 551 



forms of iiitroson. In all llioso oxporinieiits iiitrato of soda, wlioii tisod in coin 

 biiiatioii Willi 'I'lioiiias sla^' and kaiiiit. was very cfi'octivo. 



Farm wind-breaks and shelter-belts, S. K. (Jkekn (St. I'diil. Mlini.: \V('t)b 

 Pub. Co., I'.lOH. lip. >'<■>. fii/x. .id). — Tlio uses of wiiul-breaks and shelter-ltelts for 

 the protection of farm buildings and stock, especially in the prairie States. ar(> 

 discussed and directions given for propagating and planting trees suitable for 

 tliese purposes. Chapters are also given on landscape gar(l<Miing, nursery prac- 

 tices, and tree ])rotecti<)n. 



Notes on rubber-producing plants, W. Harris (Hid. Drpf. Afir. [Jaiiiaird], 

 ./ [HKKi). .\<>. II. lip. ,?'//-i.s'i). — A large aiuonnt of iiifornialioM on the various 

 rubber-producing plants has here been brought together in i)amphlet form for 

 tlie use of intending rubber i)lanters in .Taniaica. It is lielieved that the Lagos 

 silk rubber {Fiiiitiiiiiiii cldtificd) will prove to be one of the best, if not the best, 

 for many Jamaica districts. 



DISEASES OF PLANTS. 



Notes on plant pathology, G. Delacroix (Bui. Mcius. Off. Roiseig. A(/r. 

 \Parls], 5 {1906), A'o. 11, pp. 13^9-1363).— Notes are given on a bacterial canker 

 of poplar trees, a bacterial disease of potatoes, a disease of Carolina poplar, and 

 ti bacterial disease of onions. 



The bacterial disease of poplar resembles in many respects the canker produced 

 by ^'cctl•ia (liti.ssinid, Imt a thorough study of the disease and its cause shows 

 that it is due to a micrococcus, for which the author proiioses the name Micrococ- 

 cus popuU n. sp. The organism has been isolated and studied. In the author's 

 experiments he has failed to secure infection except where inoculations were 

 made through punctures or injuries caused by hail or some insect. In this way 

 he has been able to cause the disease in many instances, but only where cultures 

 were used in which the organism had been grown in a medium containing an 

 extract of the poplar bark. Where the disease is prevalent the author recom- 

 mends the burning of infested trees, or, if the attack is a slight one, cutting out 

 and burning the young branches. 



The bacterial disease of i)otatoes described is that due to liacillus plnjtoph- 

 thoruK, a disease wliich is known by the names black shank, stem rot, etc., in 

 various parts of Europe. The author calls attention to the differences between 

 tlie disease caused by this bacterium and that due to lidcillus KoJdulucoJa. He 

 reports that the bacteria are almost always accompjinied by tlie mycelium of a 

 species of Fusariuni. an observation that seems to have been overlooked by other 

 investigators. 



Tlie disease of Carolina poplar described is due to the fungus Dolhicliiza 

 jiiipulcd, and a study is given of the parasite, its method of attack, etc. The 

 author recommends for its prevention the destruction of all dead branches, etc., 

 which contain the fruiting bodies of the fungus, and spraying with Bordeaux 

 mixture or other fungicide. 



The bacterial disease of onions briefly described is said to b(> similar to, if not 

 identical with, that mentioned by a number of authors, among them Stewart 

 (E. S. R., 12, p. 50). For the prevention of this disease the rotation of crops 

 and the addition of sui»eri)hosphate of lime to the soil are recommended. 



Fungoid pests of cultivated plants, M. C. Cooke (LoiuIoii: Spoftisicoode it- 

 Co., Ltd., 1906, pp. XV + 278, pis. 2J,, figs. 23).— Brief poi.ular and technical 

 descriptions are given of a large number of fungi which are known to attack 

 cultivated plants, together with suggestions for combating them. The matirial 

 is grouped under the following heads : Pests of the flower garden, vegetable 



