1916] DISEASES OF PLANTS. 649 



Pinus longifolia, a silvicultural study, R. S. Tkoup {Indian Forest Mem., 

 Sylviculture Ser., 1 {1916), No. 1. pp. 126, pis. 33). — The study here reported is 

 based on personal investigations extending over a number of years in most of 

 the important tracts in which P. longifoUa forests occur. 



The subject matter is presented under the general headings of the distribu- 

 tion, locality, and types of foi-est ; silvicultural characters and requirements ; 

 natural regeneration ; artificial regeneration ; external dangers ; fire effects and 

 protection from fire ; tending operations ; systems of management ; and statisti- 

 cal information. 



Report on the question of field experiments, with special reference to the 

 execution of tapping experiments on estates, G. E. Coombs {Agr. Bnl. Fed. 

 Malay States, 4 {1916), No. 8, pp. 229-2^2, figs. 4).— The purpose of this report 

 is to present to rubber planters a statement of the general principles whicli 

 should govern field experiments in tapping rubber. 



Chief factors influencing the development of sal seedlings, R. S. Hole 

 {Indian Forester, 42 {1916), No. 7, pp. 335-348, pis. 6). — A summary of some of 

 the chief results of the study recently conducted at Dehra Dun, relative to the 

 factors influencing the development of sal {Shorea rohusta) seedlings. 



Newfoundland and its forest resources, D. Morris {Jour. Roy. Soc. Arts, 

 64 {1916), No. 3310, pp. 439-452; Scot. Geogr. Mag., 32 {1916), No. 8, pp. 

 353-366). — An account is given of the forest areas, principal timber trees, and 

 forest industries in Newfoundland. 



Structural timber handbook on Pacific coast woods, O. P. M. Goss and 

 C. Heinmiller {Seattle, Wash.: The West Coast Lumbermen's Assoc, 1916, pp. 

 289, figs. 38). — A handbook of information relative to the character, strength, 

 durability, and uses of Pacific coast woods. The strength and durability data 

 are based upon tests conducted by the Forest Service of the U. S. Department of 

 Agriculture and other organizations. 



The organization of the lumber industry, W. Compton {Chicago: American 

 Lumberman, 1916, pp. X-\-153, figs. 23). — This comprises an analysis of the 

 influences which have largely determined the recent course and the present 

 level of the prices of lumber in the United States. 



DISEASES OF PLANTS. 



Plant diseases in England and Wales, 1914-15 {Jour. Bd. Agr. [London's, 

 22 {1916), No. 10, pp. 931-939). — This is a statement regarding plant diseases, 

 insect pests, etc., issued in lieu of the annual report, temporarily suspended, of 

 the horticultural branch of the Board of Agriculture. 



It is stated that the mild weather in the spring of 1914 induced the summer 

 stages of the American gooseberry mildew at an earlier date than any previ- 

 ously recorded in England and led to an unusually severe attack on the fruit. 

 In 1915, the disease appeared somewhat later and was severe only where long 

 drought had weakened the resistance of the bushes. Timely aiul proper prun- 

 ing is supposed to afford complete protection and to benefit the bushes other- 

 wise. This treatment should be carried out in the period between the " soft and 

 the hard condition of the fruit." Fungicides check the disease under favorable 

 conditions, but in no case was it completely killed out by their use. American 

 gooseberry mildew is said to be known in all European countries. 



Wart disease is reported to cause loss in over 200 industrial districts. Some 

 potato varieties have now been tested many times and are considered to be com- 

 pletely immune. The number of cases in agricultural districts is very small, 

 but the occtirrence of sporadic cases suggests that the disease may be dormant 



