154 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



(Lepidum Draba) is said to have been introduced into Thanet in 1809, and 

 has since spread over Kent and Essex, becoming a pest which has hitherto 

 been difficult to eradicate, partly owing to the depth to which the rootstocks 

 will penetrate. Some have been traced toa depth of 4 feet, and both the 

 usual treatment for couch-grass and hand-weeding have only kept it in check. 

 Mr. Robson has conducted experiments by which it would appear that the 

 weed can be controlled by two annual sprayings, about May, with a mixture 

 of copper sulphate and either nitrate of soda or sulphate of ammonia, when 

 fields are being cropped with oats or other grain. 



Black Mustard {Sinapis nigra) was controlled in the same way. Some 

 scorching of the oats occurred, but this was only temporary. The effect of 

 the fertilizer used in conjunction with the blue vitriol was to stimulate the 

 growth of the grain. — G. C. G. 



Wilt Disease of Okra and the Vertieillium Wilt Problem. By C. W. Car- 

 penter {Jour. Agr. Res. xii. pp. 529-546; March 1918; plates). — Two similar 

 diseases of okra, caused respectively by Fusarium vasinfectum and Vertieillium 

 albo-atrum are described. Both are vascular parasites and are capable of 

 persisting for a long time in the soil. The treatment recommended is to save 

 seed only from healthy plants, and in extreme cases to soak seed in formalin 

 (1 part to 240 of water) before sowing. Not only is okra attacked by V. albo-atrum, 

 but also egg-plant, potato, cotton, Antirrhinum, Xanthium, Abutilon, ginseng, 

 China aster, and black raspberry. — F. J. C. 



Wireworm: Mustard-growing as a Preventive. By J. C. F. Fryer {Gard. 

 Chron. Feb. 8, 1919, p. 64). — Relates success on a farm in the East of England 

 where a first crop of Mustard on infected land has been followed by good crops. 

 When there is no other food wireworms may attack Mustard, but they eventually 

 die out, perhaps from starvation when it is grown as seed-crop, perhaps when 

 ploughed in, from some injurious substance set free in the decomposition. 



E.A.B. 



Yield, New Place Effact in Maize. By G. N. Collins {Jour. Agr. Res. xii. 

 pp. 231-243 ; Feb. 1918). — Hybrids made at different localities showed increased 

 yield as a result of transferring to a new locality, the change appearing to act 

 as a stimulus. — F. J. C. 



Yields of Fruit Trees, Relation of Variability of, to Accuracy of Field 

 Trials. By L. D. Batchelor and H. S. Reed {Jour. Agr. Res. xii. pp. 245-283 ; 

 Feb. 19 1 8). — The authors point out that one of the main factors in causing differ- 

 ences in yield of fruit trees is lack of uniformity in soil. They found that a single 

 plot of 32 trees gave far less reliable results than four 8-tree plots scattered 

 irregularly over an experimental area, and they recommend this standard for 

 cultural experiments, and for rootstock, pruning, and variety experiments, twice 

 as many plots of half as many trees. The probable error of results of various 

 groupings of trees is given. — F. J. C. 



Zanthoxylum planispinum Sieb. et Zucc. By W. J. Bean {Bot. Mag.t. 8754; 

 1918). — Rutaceae. Native of Japan. A bushy shrub of 6 to 12 feet in height, 

 branchlets almost glabrous, armed with a pair of spines at each node. The 

 leaves are semi-persistent or deciduous, 3 to 10 inches long, unifoliate, trifoliate, 

 or pinnate with five leaflets. The flowers are greenish, very small and incon- 

 spicuous. The fruits are red, about £ inch wide and contain one shining black 

 seed. — L. C. E. 



