DISEASES OF PLANTS. " 45 



After a very full review of the early literature relating to bacterial diseases 

 of plants, the author takes up and treats of the occurrence of bacteria in plants, 

 methods of their entrance, inception and progress of disease, reaction of the 

 host, individual and varietal resistance, etc. An extended chapter is devoted to 

 the subject of symbiosis, particular attention being given to that occurring be- 

 tween Bacterium U'guminomrum, or Pseitdomonas radicicola, and its host 

 plants, the Leguminoste. The author considers the organism in this case a re- 

 stricted parasite. Other forms of symbiosis are described at some length. 

 The subject of the possibility of the transfer to plants of bacteria known to 

 cause diseases of animals receives attention. The use of germicides in the 

 treatment of seeds and dormant and growing plants is discussed and formulas 

 for numerous fungicides and insecticides are given. 



In the second part of the volume the author begins the consideration of 

 specific diseases. Plant diseases due to bacteria are classified by him into 3 

 groups, vascular diseases, parenchyma diseases without hyperplasia, and 

 cankers, galls, and tumors in which there is a more or less distinct hyperplasia. 

 The disea.ses doscribetl in the present work are the cucurbit wilt due to Bacillus 

 Irachciphilus, the black rot of cruciferous plants due to Bacteriaui canipc.strr, 

 and (he yellow disease of hyacinths causetl by Bacterium hyacintht. Each of 

 these diseases is extensively treated, the symptoms, cause, distribution, charac- 

 ters of the parasite, methods of control, etc., being described. Numerous refer- 

 ences to literature are given in connection with the several topics. 



[Notes on plant diseases and their control], II. L. Russell {Wisconsin Sta. 

 Bui. 21S, pp. 20-23). — Notes are given on investigations carried on at the Wis- 

 consin Station on the use of fungicides, tobacco diseases, and the influence of 

 cold on spore germination of certain rusts (E. S. li., 2G, p. 342), and a plant 

 disease survey. 



It is reported that experiments by O. R. Butler indicate that lime sulphur 

 IH'Oved ineflicient in controlling the shot-hole fungus of the cherry, and that it 

 also caused in several instances considerable damage in strong sunlight. 



The investigations on tobacco diseases by J. Johnson include seed-bed dis- 

 eases due to Pjjthiurn dehavydnum. The results indicate that soil treatments 

 are not to be recommended, and emphasize the importance of sterilization of 

 the seed bed through burning by fires or with steam. A study was begun on the 

 stem rot of tobacco, and 2 tyi^es of fungi, a Fusarium and a Triehothecium, 

 were found in connection with the disease. 



In the report on the plant disease survey, L. R. Jones calls attention to a 

 serious leaf blight of barley due to Helmintho.sporium, losses of 25 to 75 per cent 

 of the crop being noted. Fungus diseases of orchards are said to have been 

 rather uncommon, due to the dry conditions prevailing during the summer. 

 The cheri'y leaf spot was particularly destructive in some localities, and the 

 crown gall and hairy root are said to be becoming serious. Climatic injuries, 

 due to unseasonable weather conditions, were more or less conspicuous, and the 

 author notes considerable trouble caused by Septoria and Ascochyta on peas and 

 the Fusarium and Phonia diseases of cabbages. Attention is called to the 

 necessity for the adoption of precautionary measures against the introduction 

 of such diseases. 



Some new or little-known plant diseases in Britain, F. J. Chittenden 

 {Jour. Roy. Hort. Soc. [Londoti], 37 {1912), A"o. 3, pp. 541-550) .—Hiotes are 

 given on lettuce leaf rot due to Marssonia panattoniana, leaf spot of Campanula 

 caused by Ramularia macrospora, and a streak disease of sweet peas which is 

 attributed to Tliielaria hasicola. 



The lettuce leaf rot is probably identical with that described by Selby (E. S. 

 R., S, p. 990), where the fungus was identified as M. pcrforans. 



