1920] HORTICULTURE. 237 



Frost and the prevention of damage by it (U. .*?. Drpt. Agr., Farmers' Bui. 

 J09G (l',>20), pp. ,J(S, fitjH. 26). — A practical treatise on the prevention of frost 

 injury, dealing more particularly with the protection of fruit trees. 



Introductory considerations are piven to the chanjres that take place at and 

 near the earth's surface on a frosty night and the underlying principles of frost 

 protection. The various methods and devices now being used for protection 

 against frost are discussed in detail. The pul)lication also includes a chai)ter 

 on temperatures injurious to plants, blossoms and fruit, and a description of 

 meteorological instruments and methods of determining temperatures and 

 atmosiiiieric moisture. 



[Report of the division of nursery inspection], W. C. O'Kane (A'^. 77. Agr., 

 35 (1911-18), pp. 201-2J,1, pi. i).— In addition to a brief review on the work of 

 inspecting nursery stock during the biennial period ended August 31, 1918, 

 the report contains an article on Fruit Farming in New Hampshire, with 

 special reference to apples, in which information is given relative to the plant- 

 ing and care of new orchards and the renovation of old orchards. 



New deciduous fruit station, W. L. Howard {Univ. Col. Jour. Agr., 6 (1920), 

 No. 5. pp. 10, 27). — The author outlines various projects that are being under- 

 taken at the Deciduous Fruit Station, previously noted (E. S. K., 42, p. 69-^). 



Report on the experimental orchard at Mitchell for 1919, C M. Ho»bs, 

 D. B. Johnson, and R. A. Simpson (Hoosier Hort., 1 (1920), No. 11, pp. 9-11). — 

 A brief review of progress made in the experimental orchard formerly belonging 

 to the Indiana Horticultural Society and now belonging to the Indiana Experi- 

 ment Station. A list is given of varieties of apples that have been removed as 

 either worthless or so unsuited to southern Indiana conditions as to make their 

 further trial unnecessary. 



Pollination of deciduous fruits, W. P. Tt'fts (Univ. Cnl. Jour. Agr., 6 

 (1920), No. 5, pp. IJf, 15, 29, SO, figs. 3).— A contribution from the University of 

 California, in which the author briefly considers various factors influencing 

 the pollination of fruit trees and gives a few general statements relative to 

 the results secured by the university in pollination studies with various fruits. 



[Report on fruit production in Australia] (Off. Year Book Aust., 12 

 (1901-1918), pp. 367-37S). — A statistical report on the acreage, production, and 

 export trade in fruits and fruit products in Australia for the period 1917-18, 

 with comparative data for previous years. 



Contributions from the Wisley Laboratory.— XXXV, Effect of grass on 

 apple trees, A. N. Rawes and F. J. Chittenden (Jour. Roy. Hort. Soc, Jfo 

 (1919), No. 1, pp. 116-119). — Data secured from a demonstration plat at Wisley 

 are given with a view of showing the injurious effect of starting fruit trees in 

 grass. The experimental plat was started in January, 1912, a portion of the 

 trees being grown in turf, a portion with a 3-foot circle of bare soil about the 

 Stems of the trees, and another portion clean cultivated. 



During the period 1912-1919 the growth of the trees with bare space about 

 them has been consistently greater than that of the trees with grass up to their 

 stems, but this growth has been exceeded in a marked measure by the trees in 

 cultivated ground in every case in every year. There is a marked contrast 

 between the color of the foliage of the trees in the cultivated ground and of 

 those with grass about them, the latter being such more yellow in tinge. The 

 few fruits produced on the latter trees have been on the whole smaller than 

 the many fruits on the former trees. 



The treatment of apple trees girdled by mice, E. M. STonoAun (Connecticut 

 State Sto. Bui. Inform. 10 (1920), pp. 7. /jV/.s-. <S).— The method of bridge-grafting 

 apple trees that have been girdled by mice is described and illustrated. Methods 

 for the prevention of girdling are also discussed. 



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