660 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



approached by those of Northern Africa. A large percentage of the 

 best, and only the best, is exported to Europe. The life of the hard 

 rock phosphate in Florida is variously estimated at from twenty-five to 

 one hundred years, but the deposits of pebble phosphate are con- 

 sidered almost inexhaustible, these being the two most importantj 

 classes. The former is sold on a guarantee of 77 per cent, of tri- 

 calcium phosphate, and the latter of 60 to 75 per cent. It is estimated 

 that the actual amount of phosphoric acid lost in preparing the rock 

 for the market is nearly twice as great as the quantity saved (p. 14), 

 and it is imperative to devise means of conserving and handling what 

 is now wasted, for the use of the home consumer. Experiments have 

 been made in the direction of obtaining a cheap solvent to take out 

 the phosphoric acid from the waste, but so far it has been found 

 impossible to accomplish this without dissolving out considerable 

 quantities of iron and alumina as well (p. ,16). — A. P. 



Phosphates of Tennessee, Kentucky, and Arkansas, Report 



on the Natural. By W. H. Woggaman {U.S.A. Dep. Agr., Bur. 

 Soils, Bull. 81; March 1912; map and 4 plates). — The phosphate 

 deposits of Tennessee rank next in importance to those of Florida. The 

 industry in the other two States named is still in its very early stages 

 of development. The Eeport describes the conditions prevailing in 

 these fields, with modern methods of mining and handling the rock 

 and disposing of the finished product and waste material. — A: P. 



Plant Disease Survey in the Vicinity of San Antonio, Texas. 



By F. D. Heald and F. A. Wolf (U.S.A. Dep. Agr., Bur. PI. Ind., 

 Bull. 226 ; 1912). — A record of a large number of fungus and bacterial 

 diseases of cultivated and wild plants investigated during the years 

 1909 and 1910, illustrated by nineteen good plates. 



The variety of roots attacked by Cercospora is remarkable. 



D. M. C. 



Plum Leaf-Miner, The. By C. E. Crosby (U.S.A. Exp. SH., 

 Cornell, Bull. 308; Dec. 1911; 14 figs.).— This bulletin treats of a 

 new insect enemy of the plum (Nepticula sling erlandella Kearfott). 

 In rts injurious stage it is a smooth, greenish- white larva one-sixth of 

 an inch in length, found during late June and early July feeding 

 between the outer layers of the leaf, from three to twelve mines are 

 often found in a single leaf. The trees become partially defoliated, 

 and the fruit may fall prematurely. There is little doubt about it 

 being a native American insect, and injury caused by it was first 

 reported in 1907. It is a difficult pest to control, and measures, 

 directed against the moths, eggs, and larvae have all failed, and only 

 partial success has been attained by good cultivation to destroy the 

 larvae and pupae in their cocoons. — V. G. J. 



Poisonous Salts and Fertilizers. By Oswald Schreiner and 

 J. J. Skinner (Bat. Gaz. vol. liv. pp. 31-48; July 1912; 5 figs.).— 



