191T1 DISEASES OF PLANTS. 751 



wind or funning-mill process, together with the open tank employing copper 

 sulphate and salt or formaldehyde, will probably prove to be the best available 

 means of control through seed treatment. However, this is admittedly inade- 

 quate to guard against the presence of partially smutted kernels. 



Crop rotation is the best remedy for smut left in the field from former wheat 

 crops, the rotation of oats, barley, or spring wheat with summer fallow being 

 considered as fairly safe. Continuous alteration of wheat and summer fallow 

 should be avoided. Deep plowing seems to help also, as will any operation on 

 the stubble tending to crush the smut balls. Burning is advised in case of 

 heavy stubble. Wind dissemination may occasionally be the sole cause of a 

 smutty crop. Details of experiments regarding the viability of spores in 

 the soil under varying conditions are considered to indicate that very early or 

 very late sowing and replowing the summer fallow have considerable advan- 

 tages. Another method suggested is tillage of the fallow after rains. Seed 

 should be planted when the temperature is high. 



Puccinia graminis on wheat kernels and its relation to subsequent infec- 

 tion, C. W. HuNGERFORD (Abs. in Phytopathology, 7 (1917), No. 1, p. 73). — The 

 author briefly reports experiments carried on at Madison, Wis., to determine 

 whether P. graminis is able to infect wheat through the seed. Although the 

 work has not been fully completed, the results so far obtained are considered 

 to show that seed wheat infected with P. graminis does not cause infection of 

 the wheat plant. Similar experiments have been started in cooperation with 

 the Oregon Experiment Station with wheat infected with P. glumarum. 



The Pseudopeziza leaf-spot diseases of alfalfa and red clover, F. R. Jones 

 {Ahs. in Phytopathology, 7 (.1917), No. 1, p. 70). — Studies have been made of 

 the Pseudopeziza leaf spots of alfalfa and red clover to determine possible 

 relationships of the parasites as well as other facts regarding their life 

 history. 



The author reports having found that both fungi may be obtained in pure 

 culture, slight morphological and distinct physiological differences having been 

 observed. Only ascospores have been found to be produced in nature, while 

 conidialike structures occurred in cultures. The germinating ascospores are 

 said to penetrate the epidermal cells directly, the mycelium developing within 

 the host cells and penetrating the cell walls. The fungus is considered to over- 

 winter on dead leaves which escape decay, and ascospores developed either 

 in old or new apothecia are a source of spring infection. 



Experiments in the disinfection of alfalfa seed have shown that this treat- 

 ment can not be depended upon for the prevention of leaf spot. 



Bean mosaic, V. B. Stewart and D. Reddick (Abs. in Phytopathology, 7 

 (1917), No. 1, p. 61). — The authors report the extensive occurrence in New York 

 in 1916 of a mosaic disease of beans, in some instances practically every plant 

 being affected and the plants rarely setting pods. The disease was most 

 frequently observed on pea beans, but other varieties of both- dry and snap 

 beans showed some infection. Evidence has been obtained which indicates 

 that the disease is seed borne and may be readily transferred by inoculation. 



Lima bean mosiac, J. A. McClintock (Abs. in Phytopathology, 7 (1917), 

 No. 1, pp. 60, 61). — The author reports having observed over 25 per cent of 

 several hundred plants of certain varieties of lima beans which were stunted 

 and bore the dwarfed, mottled, wavy leaves characteristic of mosaic. The 

 disease is serious, because the yield on infected plants is greatly decreased and 

 the pods are smaller and malformed. 



The celery-rot bacillus, H. Wormald (Jour. Agr. Sci. [England], 8 (1917), 

 No. 2, pp. 216-245, pis. 2). — The author, in pursuance of an account previously 

 given of a celery rot (E. S. R., 34, p. 244), states that the cause of this rot 



