236 EXPEEIMENT STATION RECOED. [Vol.36 



Witch weed or rooi-bloem (Striga lutea): A new pest of the maize crop in 

 Ehodesia, J. A. T. Walters {Rhodesia Agr. Jour., IS {1916), No. 2, pp. 234- 

 236). — This article discusses briefly the relation of this plant to maize culture 

 and suggests a method of control. The witch weed is parasitic on the roots of 

 the maize plant, which remains short and stunted and even fails to produce an 

 ear when attacked. " It is computed that a single plant frequently produces a 

 thousand seeds, and it is known that these seeds retain their germinating 

 power for years." 



Contributions to the control of weeds by means of chemical substances, 

 especially sulphuric acid, W. Gelpke (Beitrdge zur Unkrautbekdmpfung durch 

 chemische Mittel, insbesondere durch Schwefelsdure. Diss. Univ. Qiessen, 1914, 

 pp. IJf, pis. 6). — Results of experiments in weed control by means of the follow- 

 ing substances are described : Ferrous sulphate, iron chlorid, sulphuric acid, 

 sodium chlorid, sodium carbonate, borax, chrome alum, potassium bichromate, 

 manganese dioxid, acid potassium sulphate, carbolineum, carbolic acid, potash 

 soap, calcium cyanamid, nitrate of soda, sulphate of ammonia, kainit, Thomas 

 slag, and cupro-azotin. 



For the destruction of wild mustard a 15 to 20 per cent solution of ferrous 

 sulphate was found adequate. Other weeds, exclusive of the grasses, were de- 

 stroyed by the use of sulphuric acid in solutions ranging from 3 to 10 per cent 

 of acid of 66° Baume. The relatively weaker solutions applied at the rate of 

 from 1,000 to 1,500 liters per hectare (107 to 160 gal. per acre) are recom- 

 mended, and applications of this kind are reported as causing no serious injury 

 to growing grain. The use of this solution was most effective at the time the 

 weed plants had from three to five leaves. It was found that the use of sul- 

 phuric acid solution did not destroy the underground parts of those weeds natu- 

 rally provided with well-developed root systems, especially when the plants were 

 in an advanced stage of growth. 



A list of 71 references to literature on the subject is given. 



HOETICULTURE. 



Diseases and pests of garden plants, M. van den Beoek and P. J. Schenk 

 (Ziekten en Beschadigingen der Tuinhouwgewassen. Groninger: J. B. Walters, 

 1915, vols. 1, pp. XII+3S2, figs. 157; 2, pp. VIII +252, figs. 70).— Part 1 of this 

 work contains descriptive accounts of the destructive insects, birds, animals, 

 and other pests of plants, as well as the more important fungus diseases. Part 

 2 describes the various means of combating pests and diseases of garden plants. 

 A resume of the principal laws enacted in various countries relating to pests 

 and diseases of plants is included. 



Muck crops, A. E. Wilkinson {New York: Orange Jiidd Co., 1916, pp. XIII+ 

 257, figs. 82). — A treatise on vegetable growing on muck land. The first few 

 chapters discuss the nature, distribution, and value of muck and methods of 

 reclaiming muck land. The succeeding chapters treat in detail of the culture 

 of different vegetables, information being given relative to specific requirements, 

 varieties, preparation of the soil, planting, care of crops, fertilizer, harvesting, 

 marketing, yield, costs, and returns. The subject matter is drawn primarily 

 from the experience of practical men. 



[Report of horticultural investigations], O. B. Whipple {Montana Sta. Rpt. 

 1915, pp. 250-252).— In continuation of previous work (E. S. R., 33, p. 534) 

 mulching experiments were conducted with something over 20 different vege- 

 tables. The mulch, which consisted of 5 or 6 in. of straw, proved to have a 

 retarding influence on practically all crops, the warm season crops suffering the 

 most. While the mulch conserved more moisture than cultivation, it lowered the 



