^_ NOTES AND ABSTRACTS. 457 



I Diamond-backed Cabbage Moth. By W. W. Froggatt (Agr. 

 ^Gaz. N.SAY. vol. xxi. pt. 10, pp. 894-899; 6 figs.).— The larvae of this 

 ■moth (Plutella cruciferarum) may be destroyed by watering the cab- 

 bages with boiling water from a fine hose, or by spraying with kerosene 

 emulsion, or by sprinkling a mixtm^e of tobacco dust (1) and lime 

 powder (4) over the plants. — S. E. W. 



Dombeya Coria. By H. Oayeux (Rev. Hort. Feb. 16; pp. 84-85; 

 col. plate). — The plate depicts a very handsome corymb of flowers 

 .of Fritillary-bell shape about the size of Fritillaria Meleagris, but of a 

 rose colour tinged inside w^ith mauve. Very floriferous indeed, suitable 

 for cold conservatory in pots in good leafy soil. Habit robust, attaining 

 a height of over 5 feet. Doubtfully hardy as yet. Easily propagated 

 by cuttings of semi-woody shoots. — C. T. D. 



Douglas Fir. By W. H. Whellens (Trans. Boy. Scott. Arbor. Soc. 

 xxiv. 1, p. 47-51; January 1911). Observations on the growth of this 

 tree in Surrey and in Wales. The following soils are suitable: loamy 

 clays, limy soils, lighter clays; sandy soils are less favourable, and 

 gravelly soils are least suitable. Much depends on the provision of 

 shelter from wind and frost, as in these respects the Douglas is very 

 exacting. — W. G. S. 



Drought-resistant Plants and their Breeding. A. C. Dillman 

 (U.S.A. Dept. Agr., Bur. PI Ind., Bnll. 196; 40 pp. ; 4 plates).— An 

 account of the history of these investigations and reference to work 

 now in progress with Alfalfa, Sorghum, Millet, and various grasses. 

 An interesting point is the possibility of cultivating various fodder plants 

 by means of surface tillage in arid regions, and the emphasis laid on 

 this method of conserving the sub-soil water. — E. A. Bd. 



Dry-Farming in Relation to Rainfall and Evaporation. By 



' L. J. Briggs and J. 0. Belz (U.S.A. Dept. Agr., Bur. PI. Ind., Bull. 

 188, Nov. 1910; 1 plate, 23 figs.). — Alternate cropping and summer 

 tillage is generally recognized as the most highly developed dry-farm- 

 ing method, and considerable areas in Central Utah, where the annual 

 rainfall does not exceed 13 inches, are cultivated in this way (p. 8). 

 Dry-farming regions are generally considered to be those with an 

 annual rainfall of not more than 20 inches or less than 10, and there 

 are some in which other methods of dry-farming than the above give 

 better returns. The normal rainfall of any district is not the only 

 factor to be considered, for there are others of great importance which 

 are often ignored by intending settlers, such as the seasonal distribu- 

 tion of the rainfall, the frequency of torrential rains, the loss of water 

 through surface run-off, the occurrence of hail, and the amount of 

 evaporation. Each of these factors is considered in detail with 

 reference to the vast areas in the great basin and the great plains 

 where dry- farming methods are employed. Gardeners would do well 

 to ponder the fact that small rains which pack the dust mulch and 



