1019] DISEASES OF PLANTS. 543 



Biennial report of the Forestry Commission for the two fiscal years ended 

 August 31, 1918 (Him. iii>t. Forestry Com. v. //., 1911-18, \>i>. 3-127, pis. 12, 

 fig. 1). — A detailed report of the activities of the commissinn, Including tire 

 protective and white pine blister rust work, classification and description of 

 public forests, reforestation uud Improvement operations on waste and cut-over 

 land and on the State forests, organization of sawmill units for overseas 

 service, and miscellaneous operations. Recommendations are given for further 

 development of forestry In the State, and the present forest laws are appended 

 to the report. 



Pulpwood consumption and wood-pulp production in 1917, V. H. Smith 

 (U. S. Dept. Agr. Bui. 758 (1919), pp. 19, fig. 1).—A statistical report on pulp- 

 wood consumption and wood-pulp production in the United States in ll>17, 

 including comparative data for certain previous years. The data given show 

 the consumption of wood by species, States, and by processes of manufacture. 

 Imports and exports of pulpwood, wood-pulp, and paper are included. 



A total consumption in 1917 of 5,1811,075 cords of pulpwood was reported by 

 1141 establishments, an increase of 251,517 cords, or 5 per cent, over the esti- 

 mated total consumption in 11)10. The production of wood pulp totaled 3,509,- 

 938 tons — an increase of 74,938 tons, or 2 per cent, over 1916. 



DISEASES OF PLANTS. 



Handbook of plant disease and pest control, K. E. Smith, E. O. Essig, and 

 G. P. Gkay (California Sta. Circ. 204 (1918), pp. 36). — Lists are given of the 

 more common diseases and animal pests to which economic plants are subject, 

 with suggestions for their control. Sections are included on formulas for the 

 preparation of insecticides and fungicides. 



Histological studies on potato leaf roll, E. F. Artschwaueb (Jour. Ayr. Rr- 

 search [I . s.], 15 (1918), Jfo. 10, pp. 559-570, pis. 12). — The results are given 

 of cooperative investigations carried on by the Bureau of Plant Industry, 

 U. S. Department of Agriculture, and the experiment station at Cornell Uni- 

 versity on the histology of potato leaf roll as a means for the identification of 

 the disease. 



Anatomical studies of both European and American leaf roll failed to show 

 a distinct correlation with the external symptoms exhibited by the plant. 

 Typical leaf roll plants which early show external symptoms often fail to 

 exhibit extensive necrotic conditions, while plants affected with troubles 

 apparently other than leaf roll often show pathological changes In phloem and 

 cortex There is believed to be reason to suspect that the development of 

 necrotic tissues is not confined to plants affected with leaf roll but that it is 

 common to the so-called degeneration troubles and perhaps to others also. 



The pathological changes observed in connection with leaf roll are described 

 at considerable length. The rolling of the leaves and the characteristic zero- 

 phytic appearance of the plant is said to be the resultant of many interre- 

 lated changes and processes. Such changes could DOt he produced by simple 

 anatomical disturbances, nor can the results be explained on a merely 

 mechanical basis. 



Wart of potatoes: A disease new to the United States, L. O. Kunkel (U. S. 

 Dcpt. Agr., Bur. Plant Indus.. 1919, pp. 14, fi<i*. -J). -A description is given of 

 the wart disease of potatoes, due to Chrysophlyctis endobiotica, which was first 

 reported in this country in September, 1918, by J. G. Sanders, Of the Pennsyl- 

 vania Department of Agriculture. The material upon which the report was 

 based was received from Highland, Luzerne County. Pa. A survey of the 



