DISK ASKS OF PLANTS. 471 



At Tobago the author >tat«- that < lastilloa requires no shade. The experim< 

 that place indicate that aboul L2 it. apart is the best distance for Castilloa trees. 

 Tapping experiments indicate that from i to I lb. of rubber per annum may be safely 

 reckoned on as the average yield of trees L3 to It 3 ears old. Tree- 9 3 ears old 3 ield 

 about half as much. In discussing this papei J. II. Harl stated that experiments 

 carried oul in Trinidad proved that Castilloa required shade in that pi 



The article is concluded with an appendix in which Castilloa as a -hade tree for 

 caca<> is discussed. 



The India rubber of commerce, M. Cha'mney | Transvaal Agr. .I<>nr., ., 1 1904), 

 .Ye. ■''./>/>. 99-103).- An account is given of the Indin rubber of commerce, or caout- 

 chouc, in which historical statement- are given regarding it- discovery and utilization 

 and figures presented showing the sources of supply and the consumption. The prin- 

 cipal supplies come from Brazil, Central America and Mexico, Africa, Java, Borneo, 

 Madagascar, and India. The world's Bupplj in L889, the latesl figures obtainable, 

 was about 1,253,000 cwt., while the consumption was 1,250,000, leaving ;i margin of 

 only about 3,000 cwt. 



The principal species producing the caoutchouc are listed, of which the genera are 

 Willughbeia, Landolphia, Castilloa, Ficus, Bevea, and Manihot, and in addition 

 since this list was prepared large supplies of India rubber have been obtained from 

 two or more species of Kickxia, large apocynaceous trees found in central and western 

 Africa. 



New trees introduced by the Government, W. II. Evans ( Chautauquan, ;/ 

 [1905), .V". /, pp. 345-347). An account of the various forest, fruit, and ornamental 

 trees introduced by the [Jnited States Department of Agriculture from its beginning. 



An adaptation of methods in forest work, W. V. Hubbard i Forestry Quart., 

 3 ( 1905 ), No. 2, pp. 91-98). — In the preparation of a tire plan for a lumber company 

 operating in the western yellow pine type of forest, it was desired to make an esti- 

 mate of the present and future yields of timber on each quarter section separately. 



A- it was not feasible to spend time and money on a number <<\ strip surveys, a 

 variation of that method by running a series of cruisings which would give an actual 

 tally of the trees on the tract was adopted. Comparative estimates of the future 

 yield on a quarter section, from cruising valuation surveys and from strip valuation 

 surveys, are given to show the closeness of the estimates by the 2 methods. 



DISEASES OF PLANTS. 



Diseases of the apple, cherry, peach, pear, and plum; with methods of 

 treatment, E. M. Wilcox, i Alabama CoUegeSta. Bui. 132, pp. 79-14£,pls. 9, figs. 9). — 

 This bulletin, which is largely compiled from departmental and experiment station 

 publications, is designed to enable fruit growers to recognize some of the more 

 common diseases of the plants mentioned in order that they may assist the station 

 in securing data regarding the distribution and severity of the disease- in the various 



counties of the State. 



The author has avoided technical discussions of the organisms causing the diseases 

 as far a- possible, but gives suggestions which will aid in the recognition of the dis- 

 eases, and discusses method- of treatment. The material is arranged under the dif- 

 ferent headings by host plants, and chapter- are devoted to the preparation of 

 fungicides and spraying machinery. Bibliographies of the more important literature 

 are appended to the different headings. 



Some bacterial diseases of plants prevalent in Michigan, \V. <i. Backbit 

 [Michigan Sta. Bui. ..'So, pp. 903 -220, figs. 6). -Popular descriptions are given of pear 

 blight, bacteriosis of beans, black rot of cabbage', wilt of cucurbit-, soft rot of the 

 Bugar beet, and the blight of the potato, tomato, and eggplant 



