256 



vines ; Schneider-Orelli has obtained confirmatory results [R.A.E., 

 A, X, 79], and also Dewitz. Up to the present, Aphids of the vastatrix 

 form have not been found in Germany. It is doubtful whether further 

 search will reveal them, and care must be taken not to introduce this 

 form from abroad. P. pcrvastatrix, which is present, must die out 

 if only vines immune to it are grown, whereas the vastatrix form is 

 able to infest vines immune to P. pervastatrix. As regards the above 

 mentioned " immunity " of some vines to P. pervastatrix, it must be' 

 remembered that the latter attacks them, but subsequently either dies 

 or migrates, leaving them healthy and uninfested. A second group, 

 which is slightly infested for some time and then becomes free during 

 the winter, is called " half-immune " by the author, who uses the 

 term " resistant " for a third group that flourish notwithstanding 

 infestation. In contradistinction to these are the " susceptible " 

 vines. In Germany this question of the immunity of vines is more 

 important than that of the races of the Aphid, for it governs the 

 prospect of a gradual freeing of the districts infested with P. pervasta- 

 trix. The vines hitherto ascertained as being immune, half-immune 

 and resistant are enumerated. It is urged that varieties of the first 

 two groups should alone be used in the infested regions. 



Peters ( — ). Ueber die Herstellung von nikotinhaltigen Spritzflussig- 

 keiten und den Anbau von Tabak fiir solehe Zwecke. [The 

 Preparation of Nicotine Sprays and the Cultivation of Tobacco 

 for such Purposes.] — Nachrichtenblatt Deiitschen Pflanzenschtitz- 

 dienst, Berlin, i, no. 4, 1st October 1921, pp. 27-28. [Received 

 13th March 1922.] 



Owing to the shortage of tobacco extracts in Germany attention 

 is drawn to the fact that English and German investigators have 

 shown that a nicotine spray can be prepared by crumbling tobacco 

 leaves and soaking them in cold water as follows : 5 parts (by weight) 

 of leaves are soaked for a day in 33| parts water ; the water is drawn 

 off and the same operation is repeated twice ; the three lots of liquid 

 are then mixed together. If the tobacco leaves contain 3 per cent, 

 of nicotine the fluid will have a nicotine content of 0-15 per cent., 

 which can be reduced to 1 per mille by adding half as much water, 

 though this further dilution is not advised in view of the variable 

 amount of nicotine in the leaves. In England it has been found that 

 Nicotiana rustica yields more nicotine than N. tahacum. Directions 

 are given to enable vine growers to cultivate tobacco for sprajnng. 



Peters ( — ). Ueber den Nikotingehalt verschiedener Tabaksorten. 



[The Nicotine Content of various Tobaccos.] — Nachrichtenblatt 

 Deutschen Pflanzenschutzdienst, Berlin, ii, no. 2, 1st February 

 1922, p. 11. [Received 13th March 1922.] 



As a supplement to the above paper, figures of the nicotine content 

 of various tobaccos are given. 



VoGT (E.). Ein neuer Schwefelapparat. [A new Apparatus for 

 covering Plants with Sulphur.] — Nachrichtenblatt Deutschen 

 Pflanzenschutzdienst, Berlin, i, no. 4, 1st October 1921, p. 29. 

 [Received 13th March 1922.] 



A new and portable apparatus for covering plants with a film of 

 sulphur is described. By its means 300 gm. [about 10 oz.] of stick 



