566 EXPERIMENT STATION RECORD. 



the acreage having increased nearly 44 per cent during the past year. In the Malay 

 Peninsula the extent of the rubber planting is placed at 30,000 acres, in Java at 5,000 

 acres, and in India and Burma at 5,000 acres. 



Rubber in Hawaii, J. <t. Smith (Hawaii Sta. Press Bui. 13, pp. 11). — A brief 

 account of American, African, and Asiatic rubber plants, with suggestions as t<> 

 rubber culture in Hawaii. 



The most suitable species for culture in Hawaii appear to be Manihot glaziovii and 

 Ficus elastica. The first of these, it is stated, should comprise the larger proportion 

 of all new plantations because of its very rapid growth and early maturity. F. elastica 

 grows more slowly but yields much more abundantly when it finally reaches bearing 

 age. Other promising sorts for Hawaii are manicoba rubber (Hancornia speciosa) 

 and the white rubbers ( Sapium tolimense, S. verum, and S. stylare). 



It is believed that conditions in Hawaii are very favorable for the cultivation of 

 the Ceara trees. One company has already planted 100,000 seeds of this species and 

 expect to have half a million trees growing within 2 years. 



Results of tapping- experiments in a Kickxia plantation, O. Warburg 

 (Tropenpflanzer, 9 (1905), No. 7, pp. 385-390). — An account of the tapping of Kickxia 

 trees 5£ years old to determine the character of caoutchouc produced and the profit- 

 ableness of working trees of that age. 



The results obtained indicate that caoutchouc from trees of this age while not of 

 the best has considerable commercial value. It is not believed advisable to system- 

 atically work trees of this age. In certain cases, however, tapping may be profitable. 

 Thus one man can secure from 5 trees this age about 400 gm. of dry rubber per day 

 having a market value of at least 38 cts., while the cost of production is about 18 cts. 

 The experiment was preliminary to a more thorough investigation which is to be 

 undertaken. 



Estimate of cultivated rubber in the world (India Rubber Jour., n. ser., 30 

 (1905), Xo. 5, pp. 259, 260). — An account of the planting of rubber in Ceylon with an 

 estimate of the acreage of cultivated rubber in the different countries of the world in 

 1 905. The total acreage is placed at 149, 95( >. 



DISEASES OF PLANTS. 



Notes on parasitic diseases of plants, F. B(-euf (Bui. Dir. Agr. et Com. [Tunis], 

 9 (1905), No. 35, pp. 245-269, figs. 16). — A number of fungus diseases of cereals, fruit 

 trees, vegetables, and ornamental plants are described, and where remedies are 

 known suggestions are given for their use. 



Attention is called particularly to the parasitic growth of a number of species of 

 broom rape upon various vegetables, forage plants, etc. There are said to be 13 

 species of Phelypaea and 20 of Orobanche in Tunis that are known to be parasitic on 

 various plants, the most of them occurring on vegetables. Constant care that the 

 seed of broom rapes should not be included in seed of economic plants is urged. 



Diseases of plants in the Tropics, (1. Delacroix (Agr. Prat. Pays Chauds, 5 

 (1905), Nos. 29, pp. 164-173; 30, pp. 230- ? 45). — In continuation of previous papers 

 (E. S. R., 16, pp. 676, 1091), the author gives a classification of parasites, describes 

 the different forms of parasitism, and discusses the various causes of parasitic attack. 



The invasion of the host plant by fungi is due to positive chemiotactic action, and 

 facultative parasitism is also to be explained in this way. Immunity and predisposi- 

 tion to disease are determined by the chemical composition of the host. Slight 

 modifications seem able to secure some degree of immunity. The effect of age of 

 plants, soil, atmospheric conditions, etc., on disease is discussed. 



A blight of barley and oats (Jour. Bd. Agr. [London], 12 (1905), No. 6, p)p. 

 347-350, figs. 2). — A description is given of a blight of barley and oats caused by 

 Helminthosporium gramineum. 



