DISEASES OF PLANTS. 143 



spores of the rust are carried considerable distances by tlie wind. The uredo 

 pustules of P. graminis were found on winter wheat as early as upon grasses 

 near the barberry bushes, and with one exception were present upon spring 

 wheat earlier than upon grasses remote from barberries. 



The experiments seem to indicate that this rust does not spread to wheat 

 fields from grasses and that thei-e are three biological forms, one for wheat, one 

 for barley, and one for rye, oats, and various grasses. 



The uredospores of P. graminis failed to survive the winter of 1904-5 at 

 Fargo, N. Dak. The author thinks the wintering of the rust as mycelium in 

 plant tissues in North Dakota is very doubtful, but he has found the pericarp 

 of rusted wheat grains frequently filled with rust mycelium and numerous pus- 

 tules of teleutospores. The teleutospores on germination exhibited a palmella- 

 like stage. 



Attention is called to the possibility of infection of wheat by teleutospores 

 occurring in the field, and the observations suggest the need of experiments 

 along this line. 



The wintering of Puccinia graminis tritici and the infection of wheat 

 through the seed, F. J. Pritchard (Phytopathology, 1 {1911), No. 5, pp. 150- 

 15/f, pi. 1, figs. 2). — In the present paper an account is given of some investi- 

 gations which seem to confirm the conclusion in the above paper as to the oc- 

 currence of pustules containing teleutospores in wheat grains. 



Wheat -grains were selected which showed on microscopic examination in- 

 fected areas about the hilum. These were planted and after the seedlings had 

 attained a height of from 4 to 10 in. they were examined. 



As a result of his investigations the author believes that at least one source 

 of spring infection of wheat is plainly evident, for the fungus lives over winter 

 in certain wheat grains and infects the plants. The mycelium from the peri- 

 carp penetrates various parts of the seedling, invading both the intercellular 

 spaces and the cells. It soon passes into the spaces between the leaf sheaths, 

 v^here it grows rapidly and attacks the tissues at various points. This fact is 

 believed to explain the failure of Eriksson and Ward (E. S. K., 17, p. 873) to 

 trace the fungus filaments beyond the first-appearing pustules. 



An examination of samples of wheat in elevators in North Dakota showed 

 infected seeds in all the samples, and in some the infected seeds were very 

 fibundant. It is thought that experiments with hot-water treatment of the seed 

 are worth testing for the possible control of seed-borne infection. 



The effect of the club root disease upon the ash constituents of the cab- 

 bage root, II. S. Eeed {Phytopathology, 1 {1911), No. 5, pp. 159-163).— This is 

 a more extended account of investigations noted elsewhere (E. S. R., 26, p. 54). 



Irish blight, A. M. Lea {Agr. Gaz. Tasmania, 19 {1911), No. 7, pp. 357- 

 Sll, figs. 15).— An account is given of the blight of potatoes due to Phytoph- 

 thora infestans, which has appeared in a very destructive form in Tasmania. 

 The author recommends sprayiug with Bordeaux mixture for its control, and 

 outlines experiments which, although not yet fully completed, indicate a gain 

 of about 50 per cent in favor of the sprayed plants. 



Report of the pathologist, J. R. Johnston {Porto Rico Prog., 1 {1911), 

 Nos. 41, Sup., Rev. Azucarera, 1191, pt. 3, pp. 42-U; 43, Sup., Rev. Asucarera, 

 1911, pt. 4, pp. 25-31). — Descriptions are given of various diseases found upon 

 sugar cane in Porto Rico, with special mention of the root disease caused by 

 Marasmius sacchari, this fungus apparently being widespread and causing 

 much loss. In addition to brief descriptions of the diseases and suggested 

 methods of control, the author outlines some investigations that are to be 

 begun at once. 



