454 



JOUENAL OF THE flOYAL HORTICUtLTURAL SOCIETY. 



89, July 1910; 4 diagrams).— Some of the best *' poor-land " varieties 

 are not the heaviest yielders on rich soils, while a number of varieties 

 have been found which are valuable only on relatively rich land. The 

 factor of stand, with special reference to optimum stand, which may be 

 defined as the number of stalks per unit area which will produce the 

 largest yield under any given soil and climatic conditions, is shown, by 

 the results of the trials detailed, to be of considerable importance. 



A. P. 



Corsican Pine in Dorset. By J. M'Callum {Trans. Roy. Scott. 

 Arbor. Soc. xxiv. 1, p. 45-47; January 1911). — Eecommends this tree 

 for soils on Bagshot Beds where the natural herbage is heather, gorsc 

 and sedge. This tree grows well, maintains a canopy and sheds a 

 heavy layer of leaves so that the soil is kept cool and moist, an. 

 essential factor on these poor soils. — W. G. S. : 



Cotton, Egyptian, Breeding- new types. Thos. H. Kearney 

 (U.S.A. Dept. Agr., Bur. PI. Ind., Bull. 200; 34 pp.; 4 plates).— An 

 account of new types of cottons bred from recently -introduced 

 Egyptian varieties. The most valuable varieties are considered to bo 

 " mutations " and are now ready for field trials. They show the high 

 degree of uniformity so desirable for commercial purposes. — E. A. Bd. 



Cow-Pea Curculio, The. By Geo. G. Ainshe {U.S.A. Dept. Agr., 

 Bur. Efitom., Bull. 85, pt. viii. ; Sept. 1910; 3 figs.). — The cow-pea 

 weevil passes the winter in its adult stage, hibernating only when its 

 food-supply is cut off by frosts in the autumn. It emerges in the | 

 spring and immediately connnences to feed on cotton or other fresh I 

 young plants as they appear until the cow-pea pods are sufficiently j 

 grown to permit oviposition. | 



When breeding, this weevil confines itself almost entirely to the 

 cow-pea and allied legumes. Young cotton is frequently damaged by 

 it in the spring, but as this trouble occurs only on land on which cow- 

 peas werei grown the previous year, it is apparent that cotton is a 

 food plant rather from necessity than choice. — V. G. J. 



Crown-g-all of the Grape, Field Studies of the. By G. G. 



lledgcock {U.S.A. Dept. Agr., Bur. PI. hid.. Bull. 183; July 1910; 

 plates). — A disease known in America as black-knot, crown-knot, root- 

 knot, crown-gall, and root tumour, and in Europe as grind, kropf, 

 broussins, rogna, tuberculosi, &c. is described. Two forms are dis- 

 tinguished: a rough, often hard excrescence on stems, and a soft form 

 on the root. The disease is probably found wherever the vine is grown. 

 It is caused by the attack of Bacillus tumefaciens (see Jour. E.H.S.( 

 xxxvi., p. 779), and the entrance of the disease is favoured by injuries 

 such as are caused through freezing and late frosts, pruning, &c. 

 The effect is very destructive, often killing or stunting nearly al. 

 the vines in a vineyard in a few years. The galls usually develop 



