505 



Richards (P. B.). Methods and Materials for the Control of Insect 

 Pests. (Part 4.) — Agric. Bull. Fed. Malay States, Kuala Lumpur, 

 iii, nos. 6-7, March- April 1915, pp. 237-241. 



Nicotine is obtainable in the form of tobacco extract, which is 

 prepared on a large scale by treating coarse tobacco leaves with hot 

 water and distilling the solution obtained. In France the extract is 

 largely used for combating vine pests. Iij America " Blackleaf 40 " 

 contains 40 per cent, of nicotine sulphate : " Nico-fume " contains 

 40 per cent, of free nicotine, and " Blackleaf " Extract from 2-3 per 

 cent, nicotine. The spray is useful for .small insects and mites, but 

 is too expensive except for valuable crops. Nicotiana ruslica contains 

 4-5 per cent, of nicotine in the dried leaf. To make the wash, 

 the leaves should be broken up finely and extracted in three successive 

 lots of water at the rate of 1 gal. to 1 lb. of leaves. The tobacco 

 should be steeped for 24 hours in each lot of water and the temperature 

 should not exceed 140° F. The stems and leaf- veins are first crushed, 

 then soaked in water at the rate of 1 gal. to 5 lb. The extract so 

 obtained contains about 0*12 per cent, of nicotine. Tobacco extract 

 is rendered more effective by the addition of soap at the rate of 

 2 to 4 lb. to 100 gals, of the wash. Hops will stand spraying with 

 0"08 per cent, solution, at which strength rose shoots are injured. 

 A strength of 0"025 per cent, will kill aphids and. thrips. For bug 

 nymphs and scale-insects, the addition of soap is necessary. Hellebore 

 spray is obtained from the roots of Veratnmi viride and V. album, 

 Helleborus niger and H. foetidus. From 5 to 7 A lb. of finely powdered 

 root are stirred up in 100 gals, water. When used as a dusting powder, 

 the root is mixed with three times its weight of flour, gypsum or wood 

 ash. The use of Veratrum album, and F. viride is recommended for 

 ripening fruit, since the poisonous properties disappear in 3-4 days. 

 Quassia spray is obtained by exhausting quassia chips with hot water. 



Storey (G. A.). Notes on Large Scale Experiments against the Pink 

 Boll Worm in Cotton Seed. — Agric. J I. Egypt, Cairo, iv, no. 2, 

 (1914) 1915, pp. 115-124, 2 plans. [Received 30th June 1915.] 



The hot air treatment and fumigation methods previously 

 recommended lor trial [see this Review, Ser. A, ii, p. 218] have been 

 tested on a large scale. A full description is given of the hot air 

 machine, which was a double-walled wooden box 13 feet long, 

 2 feet high, and 2 feet broad, heated by steam pipes. In this 

 the cotton seed was passed on an endless canvas band. The 

 results are set out in a table. -It was found that with this particular 

 machine treatment of the seed (i) for 3.^ minutes at temperatures 

 between 159° and 177° F., (ii) for 6h minute^s between 140° and 159° F., 

 and (iii) for lO.l minutes at 140° F., succeeded in killing all the larvae 

 without injuring germination. Three and a half minutes at tempera- 

 tures of 177° and 195° F. does not injure the seed much, if at all. The 

 running conditions most suitable for this particular machine are 

 undoubtedly 3 J minutes at 167° F. Longer times are inadvisable 

 owing to the immense size of the machine which would be necessary 



