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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



gallon of water. The application left a thick coat of whitewash on the 

 tree, entirely obscuring the bark and leaving the plant snow-white. At 

 the time of treatment the buds had not started. This limewash held 

 very well except that it cracked and scaled off a little in spots, due to the 

 action of the wind. In the main, however, the bark of the tree remained 

 snow-white and thickly covered for three or four weeks, in fact at the 

 end of the summer the lime still adhered to some slight extent. The 

 tree came into bloom and leaf later on without any checking from the 

 application. The adult female scales were not affected, apparently, at all 

 by this application, rather to our disappointment, but it was still hoped 

 that the lime-coating would remain and prevent the young scales from 

 settling on the bark. The young of this species, however, appeared very 

 late in the spring and, unfortunately, before that time the lime had so 

 cracked and scaled off in spots that little benefit was gained from its 

 presence, and the second brood at least of this species again completely 

 covered the tree." This pure limewash appears, therefore, to be of little 

 value against the scale insects belonging to the sub-family Diasjnnce, 

 which includes our common "Mussel scale " {Mytilas2)is j^omorum) and the 

 Oyster-shell Bark-louse [Aspidiotus ostrccBformis), both of which are 

 injurious to fruit trees in this country. (See B.H.S. Journal, vol. xxiii. 

 p. 219 et seq.) 



The experiments with the other substances did not produce very 

 satisfactory results also. — B. N. 



Insecticides, Experiments upon Potatos with. By Chas. D. 

 Woods (U.S.A. St. Bd. Maine, Ann. Bep. 1900, table). — In the annual 

 report of the Maine Agricultural Experiment Station, page 171, is a 

 valuable report of the results of various experiments with such insecti- 

 cides as Paris green, arsenate of lead, &c. Careful field notes and 

 practical directions are given. — V. J. M. 



Insect Enemies of the Spruce in the North-East. By A. D. 



Hopkins {U.S.A. Dep. Agr. Div. Ent. Bull. 28 (new series), 1901; 

 48 pages, with 16 plates). — The investigations undertaken to determine 

 the cause or causes of a prevailing unhealthy condition of the Spruce 

 in certain sections of the forests of Maine, New Hampshire, and Vermont 

 are given in this pamphlet. A large amount of dead Spruce was 

 observed throughout the area traversed. The dead trees were not 

 confined to any particular soil, altitude, or exposure, but were found 

 wherever the diameter of the trees was over twelve inches. The first 

 indication of the unheakhiness of a tree is the appearance of a pale tint 

 in the leaves of the upper branches, or tops : these soon fall, and a slight 

 jar or wind will cause a shower of the needles to fall. There are two 

 causes of death, the work of beetles in the middle bark, and the presence 

 of fungi in the bark and wood. The chief offender is a beetle belonging 

 to the family ScolytidcB {Dendroctonus piceaperda). The life-history of 

 this insect is given with full details, illustrated with some very good 

 plates copied from photographs by one of the half-tone processes. This 

 insect is attacked by two parasites ; one, a small parasitic four- winged 

 fly, Bracon simplex, which deposits its eggs in the larvae ; and a beetle 



