142 



in confidence, but only those materials are tested for which the maker 

 submits working instructions. The results are published in the case 

 of materials already on the market ; in the case of new ones, the 

 publication of results may be withheld at the request of the maker. 



RiEHM (E.). Die Regelung des Handels mit Pflanzenschutzmitteln. 



[The Regulation of Trade in Substances for Plant Protection.] — ■ 

 'Angew. Bot., ii, 1920, pp. 302-308. (Abstract in Cenfralbl. 

 Bakt. Paras. InfekL, Jena, lite Abt., Iv. no. 14-20, 18th January 

 1922, p. 368.) 



Existing legislation with regard to insecticides and other substances 

 used in plant protection in the United States, Switzerland, Denmark 

 and Saxony are compared. The author does not approve of clauses 

 requiring the publication of formulae (often the result of prolonged 

 experiments), or of the fixing of a maximum price, as costly research 

 would be hindered thereby. 



Sertz (H.). Ueber die Wirkung von Fluorwasserstoff und Fluor- 

 silizium auf die lebende Pflanze. [The x\ction of Hydrogen 

 Fluoride and Silicon Fluoride on the living Plant.] — Tharandt. 

 forstl. Jahrb., Ixxii, 1921, pp. 1-13. (Abstract in Centralhl. 

 Bakt. Paras. Infekt., Jena, lite Abt., Iv, no. 14-20, 18th January 

 1922, p. 373.) 



Experiments show that hydrogen fluoride and silicon fluoride are 

 quite unsuitable for use in fumigation, as they are very injurious to 

 living plants. 



WiLHELMi (J.) Zur Ausgestaltung der Schadlingsbekampfung. [On 

 the Full Development of Work against Pests. 1 — Naturw. Wochen- 

 schr., N.S. XX, 1921, pp. 312-316. (Abstract in Centralbl. 

 Bakt. Paras. Infekt., Jena, lite Abt., Iv, no. 14-20, 18th Januarv 

 1922, pp. 395-396.) 



Salient points in the work of combating insect pests in Germany 

 are the founding of the German Society for Applied Entomology, in 

 1913, the work of the Technical Committee against Pests, which was 

 attached to the Ministry for War, and the establishment of the German 

 Company for Combating Pests. The present position is discussed. 

 It is very desirable that such facilities as exist should be enlarged, 

 and a plan is given on the lines of which it is suggested that measures 

 should be organised in Germany. 



Neumeister ( — ). Nonnengefahr ftir Saehsen. [The Nun Moth 

 Danger in Saxony.] — Tharandt. forstl. Jahrb., Ixxii, 1921, pp. 62-64. 

 (Acstract in Centralbl. Bakt. Paras. Infekt., Jena, Ilte Abt., 

 Iv, no. 14-20, 18th January 1922, p. 408.) 



In view of the prospective danger of an outbreak of the nun moth 

 [Liparis monacha], which was abundant in some districts of Saxony 

 in 1920, ofiticial counts must be made of eggs on four or five felled 

 trunks in every 2| acres. Remedial measures are obligatory if more 

 than 100 eggs are found on a spruce trunk, and 150 on pine. 



