842 EXPERIMENT STATION RECORD. 



DISEASES OF PLANTS. 



Beport of the pliytopathological section of the agricultural institute, 1906, 

 E. ilARCHAL (Bill. Ayr. [Bna^scls], 23 {1901), No. 1, pi). ^.'M''' ) -—After u 

 tabuhir list of diseases that have been reported upon during the year, notes are 

 given on a number of those which were most troublesome, with suggestions for 

 their control. Among those described are bean anthracnose, downy mildew of 

 grapes, cherry scab, and apple scab. 



Some publications in 1906 on the heteroecism and specialization of 

 Uredinese, E. Fischer (Bot. Ztg.. 2. AM., 65 (1907), No. .'/, pp- 4^-54).— The 

 author briefly reviews tbe published results of Arthur, Fischer, Miiller, 

 Schneider, Shear, Tranzschel, and others relating to the heteroecism of various 

 &pecies of Uredinere and the specialization of forms on certain host plants. 

 Most of these publications have been noted elsewhere. 



Volunteer wheat and rust, B. J. Butler {Agr. Jour. India, 2 {1901), No. 

 1. pp. 99. 100). — It is said that in some countries the outbreak of rust in wheat 

 is ascribed to the carrying over of the fungus on volunteer wheat. This theoi'y 

 of propagating the fungus can hardly be accepted in India, as it is said that the 

 weather is so hot after a crop is cut that usually no plants can be found until 

 the next crop is sown. In addition, it has been learned that the rust spores 

 themselves can not survive exposure to tbe intense heat that is experienced 

 in the hot weather montbs. In order to explain the annual appearance of rust 

 in India through the medium of volunteer wbeat, tbe author says that it will be 

 necessary to assume a combination of conditions tliat does not exist. 



Smut diseases of cereals and a method for combating them, O. Appel and 

 (i. Gassner {Mitt. K. Biol. Aiist. Land n. Forstir., 1901, No. 3, pp. 20, fig.^. S).—A 

 sunnnary is given of the present state of information regarding cereal rusts, the 

 species described being TJstilago tritici, U. liordci, TJ. jensenii, ZJ. aveme, V. 

 levis, Tillctia tritici, and T. Icvis. 



Since the infection takes place thx'ough the flowers and treatment of the seed 

 is of doubtful expediency, the author recommends for tbe prevention of loose 

 smut of wheat and barley the selection of seed from isolated noninfested 

 regions. For the bunt or stinking smut of wheat, black or hard smut of barley, 

 and botli the loose and covered smuts of oats seed treatment is said to be 

 efticient. 



A description is given of a form of apparatus that has l)een devised for the 

 hot-water treatment of seed, in which the proper temperature is maintained by 

 steam. 



A grass-killing slime mold, .1. W. IIarshberger {Pror. Anicr. Phil. Hoc, 

 //.J {1906), No. IS-',, pp. 21 1-21 3). -^n August, 1905, tbe author's attention was 

 called to a lawn in which the grass was being destroyed in areas varying from 

 a few inches to several feet- in diameter. The trouble seemed to begin after a 

 series of night showers, the grass having become blackened here and there over 

 the lawn. Subsequently it was reported tbat only the blades of the lawn grasses 

 were destroyed, and that after the disease had disap[)eared tbe grass regained 

 its fresh bright green color. 



Specimens of the dead grass were submitted for examination, and the author 

 reports having found tbem infested with tbe slime mold {Pliysaruin cincreuni). 

 The abundant production of the Plasmodium of this mold had caused the de- 

 struction of the grass, and its occurrence on the living grass leaves demonstrates 

 that the organism had changed its habit from that of a saprophytic life to a 

 parasitic one. 



Concerning a fungus-free darnel, E. IIannig {Bot. Ztg., 1. AM., 65 {1901), 

 No. 2, pp. 25-38). — A report is given on studies of Lolimn temulentmn, particu- 



