DISEASES OF PLANTS. 649 



Consumption of wood preservatives and quantity of wood treated in the 

 United States in 1910, H. S. Sackett {U. S. Dcpt. Agr., Forest Serv. Giro. 

 ISG, pp. ■'/). — This is a statistical review based upon reports of 49 firms rep- 

 resenting 71 treating plants, or 96 per cent of the plants in operation during 

 the year. 



The principal preservatives used, in the order named, are creosote, zinc 

 chlorid, corrosive sublimate, and crude oil. In 1910 over 63 million gals, of 

 creosote, of which 71 per cent was imported principally from England and 

 Germany, and 16,802,532 lbs. of zinc chlorid, obtained from domestic sources, 

 were used. The wood treated included crossties, piling, poles, paving blocks, 

 construction timbers, cross arms, lumber, etc. The total material treated has 

 increased from 68,228,299 cu. ft. in 1907 to 100,079.444 cu. ft. in 1910. 



Grazing and floods: A study of conditions in the Manti National Forest, 

 Utah, li. V. R. Reynolds (U. fe'. Dept. Agr., Forest Serv. Bill. 91, pp. 16. pis. 5, 

 map 1). — The present study, which illustrates the harmful effect of overgrazing 

 upon stream flow, is discussed under the following general headings: (Jrazing 

 history, past floods, damage from floods, efforts to prevent damage, conditions 

 affecting floods, including topography, soil, ground cover, rainfall and tor- 

 rential run-off, and the future regulation of grazing. 



It is concluded that the torrents that have devastated this region within 

 the last 20 years have been caused primarily by overgrazing, and that they can 

 be largely controlled, if not entirely eliminated, by restoration of the natural 

 protective cover of shrubs and grasses. 



The National Forest Manual: Trespass (£/. 8. Dept. Agr., Forest Serv., 

 1911, pp. 23). — This pamphlet, which constitutes a part of the Use Book (E. S. 

 R., 22, p. 542), comprises regulations of the Secretary of Agriculture issued 

 to take effect September 1, 1911, appertaining to trespass upon the National 

 Forests, and instruction to forest officers thereunder. 



DISEASES OF PLANTS. 



[Mycological studies], H. L. Bolley {Xorth Dakota Sta. Rpt. 1909, pp. 

 3^-56, 02-66). — The results are given of investigations on diseases of wheat, 

 flax, and potatoes, but mainly on wheat diseases caused by species of Colleto- 

 trichum, Macrosporium, Helmiuthosporium, and Fusarium which infect the 

 stem, blades, and grain of the wheat and persist in the soil, thereby producing 

 a species of wheat-sick soil. 



Tables are given showing the results of various experiments with wheat and 

 flax, including continuous cultures of wheat and flax in sand and in soil, and 

 qualitative determinations of the fungi found in unsterilized and sterilized 

 wheat plants. The bacteriological content of wheat seeds on an experimental 

 plat and the examination of miscellaneous plant disease specimens are reported. 



In the work with flax it was found that in addition to flax wilt there is a 

 destructive canker of flax caused by a species of Colletotrichum, and also a dis- 

 ease of the flax bolls caused by species of Alternaria and MacrosiDorium. The 

 flax canker seems to be confined largely to the western and northwestern dry 

 regions of North Dakota. It is due to C. lini, and is characterized by a peculiar 

 breaking off of the nearly mature flax plants at a point near the ground line. 

 The disease is often found on new fields (virgin prairie sod) of flax, and is sup- 

 posed to be caused by infection from native wild flax, or, -more probably, by the 

 use of internally infected seed, as flax seed are often found in which the seed 

 leaves have cankers before the seed are matured. The canker disease is largely 

 amenable to seed selection and seed treatment, but wilt-resistant varieties of 

 flax are not immune to the canker. 



