191T] DISEASES OF PLANTS. 839 



citrus knot; bnd rot of coconut palm; root disease (Fomes semitostus) of 

 Hevea; rose mildew (SphCBrotheca pannosa) ; black blight (Dimerosporium 

 mangiferum) of Hibiscus, Ixora, Barbados cherry, and Bougainvillea, besides 

 several other plants ; and a bacterial disease of orchids. 



Scolecotriclium graminls on timothy, orchard grass, and other grasses, 

 A. G. Johnson and C. W. Hungerford {Ahs. in Phytopathology, 7 (1911), No. 1, 

 p. 69). — The authors report having observed S. graminis on timothy and orchard 

 grass at various points from Wisconsin to the Pacific coast. The fungus is 

 said to cause a serious disease of these hosts, especially in Wisconsin. A num- 

 ber of other species of grass are reported as hosts of the fungus, and observa- 

 tions at Madison, Wis., are considered to show that it overwinters readily in 

 tufts of orchard grass and timothy. 



Bacteria of barley blight seed-borne, L. R. Jones, A. G. Johnson, and C. S. 

 Reddy (Abs. in Phytopathology, 7 (1911), No. 1, p. 60). — In continuation of a 

 previous study of a bacterial blight of barley (E. S. R., 35, p. 845), the authors 

 have given special attention to the dissemination of the disease over long dis- 

 tances, and they conclude that the organism may be carried with the seed grain 

 and remain viable after at least two years of dormancy. Preliminary experi- 

 ments are said to indicate that the organism may be destroyed by seed disin- 

 fection. 



CJom disease caused by Phyllachora graminis, Noba E. Dat.rey (Phyto- 

 pathology, 7 (1917), No. 1, pp. 55, 56, fig. 1). — A brief account is given of obser- 

 vations on the fungus P. graminis on leaves of maize collected in Porto Rico. 

 A detailed description of the disease and fungus is to be given in a subsequent 

 publication. 



Smut diseases of wheat, W. B. Meeceb (Jour. Bd. Agr. [London^, 2S (1916), 

 No. 7, pp. 6SS-643, figs. 2). — Along with a brief discussion of several smuts of 

 economic cereals, the author gives brief notes of studies, to be published else- 

 where in greater detail, regarding the life history of TJstilago tritid, the cause 

 of loose smut of wheat. 



The fungus is said to be capable of entering the young grain, but not the 

 seedling. The chlamydospores germinate Inside the flower and the tube pene- 

 trates the immature grain, giving rise to a small amount of mycelium in the 

 embryo and the starchy endosperm, the grain developing in spite of this fact. 

 When the Infected grains are sown, the fungus grows with the young plant In a 

 way similar to that of the bunt fungus. When the head begins to form, the 

 mycelium begins to grow more rapidly, branches profusely, and forms a large 

 number of spores, which are at first held together by a gelatinous substance en- 

 closed in a thin membrane which usually ruptui'es as the ear emerges. Unless 

 these spores thus freed reach a flower they become harmless, probably in a 

 few days. 



The control measures tried up to the present time are outlined. The fungus 

 can not be reached with chemical fungicides. The method of picking out the 

 smutted heads from the standing crops, while fairly effective, is not practi- 

 cable on a large scale. Selection of seed on the basis of size or weight Is In- 

 effective. Steam has given some fair results, but Is not considered safe as a 

 seed treatment. Forcing hot water through the seed grain Is Impracticable. 

 Hot-air kilns do not heat the grain evenly. Rolling the grain in heated drums 

 has met with a measure of success. The treatment found most eJBfective Is to 

 soak the wheat in water at a temperature of 25 to 30° C. (77 to 86° F.) for 

 four hours and then for 10 minutes at 52 to 54° C. (125.6 to 129.2° F.), this 

 treatment destroying the fungus with a comparatively slight lowering of 

 germlnabllity. 



