DISEASES OF PLANTS. 155 



tected and burned and either gas Lime or quicklime applied to the land where the 

 disease has existed. 



Rusts of grain crops, J. Fletcheb [Canada Expt. Farms Rpis. 1904, pp. ■■'•■- 

 £66 ). — Popular notes are given describing the cause of the wheat rusts, and the relation 

 of the organism to wheal and other host plants, and suggestions for preventing loss. 

 The principal suggestion is plant breeding along the line of rusl resistance. 



New studies of the vegetative life of yellow grain rusts, .1. Eriksson A 

 Lqndtbr. Akad. Handl. och Tidskr., 43 {1904). No. 3, pp. ?S4 -'/'•'• An account of 

 recenl investigations conducted by the author on this subject. These further cor- 

 roborate the views previously sel forth, thai the yellow grain rustsat least can live 

 within the wheal plant from the time of germination in the fall until June the nexl 

 year in the form of a m\ coplasma, finally producing a protomycelium, and thai from 

 this form contagion ma\ spread, as well as later on from uredospores. The efforts 

 toward eradication of grain rusts must, therefore, be directed againsl tin- germ of 

 disease in the form of mycoplasma in the plant itself, rather than againsl the conta- 

 gion from without through spores carried about by wind and weather. Breeding 

 experiments to secure rust-resistant varieties must therefore receive still mote atten- 

 tion than has heretofore been the case. — f. w. woll. 



The formalin treatment of grain smut and its application by means of 

 Dehne's disinfection machine, S. Rhodin (K. Landtbr. Akad. Handl. och Tidskr., 

 .;.)' [1904), No. 5, pp.368-37£). — Experiments were conducted with wheat and barley 

 treated in the Dehne disinfection machine. 



The treatment only slightly decreased the germination and the germinative energy 

 of the seed grain, and the treated grain was free from smul in every case. The 

 capacity of the machine is 1,000 kg. of grain per 30 minutes. In the experiments 

 conducted by the author, 200 cc. of 40 per cent formaldehyde was dissolved in 70 

 liters of water for oats, and in 50 liters for other kinds of small grains. — f. w. woll. 



BurrilTs bacterial disease of broom corn, E. F. Smith and Florence Hedges 

 [Abs. in Science, n. ser., 21 I 1905 i, No. 535, pp. 502, 503). — The occurrence of a bacte- 

 rial disease of hrooin corn in Washington, I >. ('., in 1904 is noted. 



The affected plants exhibited the characteristic elongating red-brown spots, fol- 

 lowed by the death of the leaves. The disease began on the lower leaves, but by 

 the end of September had reached the top of the plants and had destroyed all the 

 lower leaves and badly spotted the remainder. A microscopic examination of the 

 spots Bhowed a bacterial focus to he present in each one. The infection was found 

 to take place by way ol the Btomata and was favored by rainfall or dew. 



The authors separated the organism and describe its action in various media, as 

 well as determining a number of its cultural characteristics. Some varieties of broom 

 coi ii ate said to be much more susceptible to the disease than others, and it is hoped 

 that through resistant plants the disease may be overcome. 



Spraying potatoes for the prevention of blight and rot, \V. T. M kOOUN ( ( an- 

 ini'i Expt. Form* Rpts. 1904, i>i> 131-134)'- A report is given on comparative testson 

 different plats of potatoes sprayed with Bordeaux mixture and Bug Death, Bordeaux 

 mixture and Paris green, soda Bordeaux and Pans green, and the insecticide- used 

 separately. 



Five applications were given the vines beginning Jul} 2 and continuing at inter- 

 vals of about LOdays. The potatoes were dug Oetobei 6 and the yields, increase in 

 crop, and cost of spraying are shown in tabular torm. It appears that the Bordeaux- 

 Bug Death mixture gave the greatest increase, the net increase in value amounting 

 to $21.86 per acre. This was followed bj ordinary Bordeaux mixture and Paris green, 

 winch gave a net increase ol $17.68 per acre The exact cos! of application is not 

 given, the expense of applying the fungicides to small plats being relatively much 

 greater than had larger tracts been used. 



