DISEASES OF PLANTS. 847 



recommends the removal of all diseased plants, drenching the place where the 

 infected plant stood with Bordeaux mixture or copper sulphate solution, and 

 rotation with unsusceptible crops. 



A disease of tomatoes, F. T. Brooks and S. R. Price (New Phytol., 12 

 (191S), No. 1, pp. 13-21, figs. 13; ahs. in Bot. Centbl., 123 {1913), No. 2, p. 30).— 

 This is an account of the authors' experiments with the fungus called Ascuchyta 

 citrullina, also known by its pycnidial stage as MycosphcereJla citruUina, and 

 found on muskmelons in the United States, as stated by Grossenbacher (E. S. 

 R., 21, p. 148), and on tomato and cucumber plants in England by Massee 

 (E. 8. R., 22, p. 50). 



" The results of these inoculation experiments make it clear that the fungus 

 causing a rot of the fruit is identical with that which induces canker on the 

 stem. ... In view of the apparent absence of a perithecial stage in this country 

 and of the fact that the tomato plant is an annual, it is not clear how the 

 disease is propagated fi-om one year to another. . . . There is no evidence yet 

 that the fungus is propagated in the seed. On out-door plants the disease does 

 not appear to develop until almost fully grown. Only 3 per cent of the plants 

 were affected and the distribution of diseased plants was sporadic, so that the 

 disease is not likely to become a serious pest to growers of out-door tomatoes." 



Tomato diseases, P. H. Rolfs (Florida Sta. Bui. Ill, pp. 33-^8, figs. 2). — 

 Descriptions are given of rust (Macrosporium solani), fungus blight (Fusarium 

 sp.), Sclerotium blight (S. rolfsii), bacterial blight (Bacillus solanacearum) , 

 dropping of bloom buds, leaf curl or roll leaf, damping off, hollow stem, black 

 spot (Alternaria solani), and blossom-end rot, which is thought probably to be 

 caused by different species of fungi and a bacterium. In addition to the 

 descriptions of these diseases, remedies are suggested so far as they are known. 



Silver leaf disease, II, F. T. Brooks (Jour. Agr. Sci. [England], 5 (1913), 

 No. 3, pp. 288-308, pis. 2). — Reporting on further studies of silver leaf disease 

 (E. S. R., 26, p. 448) and quoting a recent report by Giissow (E. S. R.. 28, p. 

 348), the author concludes that silver leaf is a pathological condition of wide- 

 spread distribution, the chief cause of which is the fungus Stereum purjmreuui, 

 although examples of silvered foliage have come under observation which can 

 not be attributed to the action of this fungus. Silver leaf is considered to be a 

 general pathological phenomenon which may be caused in various ways, 

 although at present only one of these agents is known with certainty. It 

 appears likely that it may be caused also by physiological disturbances which 

 are not connected with the action of any parasitic organism, such as a dis- 

 turbance in the transpiration current induced by the presence of the fungus. 

 The author thinks the manifestation of silver leaf depends partly upon leaf 

 structure, and as the phenomenon of silver leaf can not always be attributed 

 to 8. purpureum the destructive influence is not invariably accompanied by this 

 peculiar affection of the leaves. 



A bibliography is appended. 



The Jonathan spot rot, M. T. Cook and G. W. Martin (Phytopathology, 3 

 (1913), No. 2, pp. 119, 120). — Attention is called to the Jonathan spot, a storage 

 trouble that often nuikes its appeai-ance soon after the fruit comes from the 

 cold storage. In addition to the Jonathan a number of other species of apple 

 are similarly affected. 



An examination made of the spots showed that fully 90 per cent of them 

 gave a luxuriant growth of Alternaria, and repeated inoculation experiments 

 indicated that this fungus can cause typical spot rot. 



The authors state that there are three different species or varieties of Alter- 

 naria causing apple rots, one causing a blossom-end and core rot, one a dry 



