614 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Apple-Leaf hopper. By F. L. Washburn (U.S.A. Exp. Sin., 

 Mitotiesota, llth Ann. Reft. 1909 ; pp. 145-164 ; plates). — A careful 

 account of the apple-leaf hopper {Empoascd mali Le B. ^Typhlocyha 

 pJiotophila Berg.) is given. The young appear on apple trees soon 

 after the leaf buds burst, and reach maturity about forty days later, 

 there being two, and possibly three, broods during the year. The 

 adult, which is green (the younger stages of the nymphs being white), 

 measures about -J inch in length. The summer eggs are laid in the 

 petioles of clover, apple, and probably other food plants, the winter 

 eggs being placed in blister-like swellings on the bark of apple trees. 

 The insect occurs on many other plants besides apple, including plum, 

 maple, oak, black oak, thorn apple, basswood, hazel, box elder, choke 

 cherry, sumac, European birch, cut-leaf birch, syringa, snowball, 

 r,aspberry, blackberry, bush beans, corn, clover, lucerne, sugar beet, 

 buckwheat, dahlia, hemp, rhubarb, potato, and grasses. Nursery 

 stock suffers most from its attacks, and the best results have been 

 obtained by carrying a canvas screen smeared with " tangle-foot " 

 through the plantation, to catch the adult insects upon. The leaves 

 when badly attacked curl as though attacked by the leaf -curling aphis, 

 but when this has not occurred to a serious extent a spray made by 

 dissolving 1 lb. fish oil soap in 10 gallons of water may be used with 

 advantage. A record of experiments designed against the pest is given. 



F. J. C. 



Apple Orcharding-, Spraying- an Essential Part of. By E. A. 



Emerson, E. E. Howard, and V. V. Westgate {U.S.A. Exp. Stn., 

 Nehmska, Bull. 119; March 1911; 8 figs.). — During the last five years 

 demonstrations have been made in twenty-two orchards distributed 

 over the eastern part of this State, one of the objects being to deter- 

 mine whether apple insects and diseases could be controlled profitably. 

 The difference in the annual value of the crops from the sprayed and 

 the unsprayed trees averaged $1.54 per tree, the cost being estimated 

 at $0.24 per tree. On the basis of fifty trees to the acre the average 

 net gain from spraying worked out at $64.55 from each acre per annum 

 (p. 9). It is suggested that for the spraying of small orchards, such 

 as those attached to farm homesteads, spraying outfits should be run 

 on the same plan as threshing machines, a man buying a power sprayer 

 and letting it out to his neighbours, in which way the machine would 

 not only pay for itself, but reduce to a minimum the possibility of 

 infection to his own orchard from outside sources. — A. P. 



Atmospheric Impurities in and near an Industrial Town, 

 The Nature, Distribution, and Effects upon Vegetation of. By 



Chas. Crowther and A. G. Euston {Jour. Agr. Sci., vol. iv. pt. i. 

 pp. 25-55 ; May 1911). — The authors based their conclusions on a three- 

 years' service of analyses of rain samples collected at Garforth, a year's 

 series collected in different parts of Leeds, and a variety of investigations 



