63 



of the United Kingdom, where economic difficulties and disadvantages 

 have discouraged the growing of tobacco for insecticides. The 

 immense quantities of refuse tobacco stalks that are regularly- 

 abandoned to the Crown have a considerable potential value as a 

 source of nicotine and plant foods, especially potash, of which there is 

 at present a great shortage. 



The Department has devised a cheap and efficient means of utilising 

 the insecticidal and manurial value of refuse tobacco stalks which 

 could be practised on any farm, and which consists in dissolving the 

 nicotine out of tobacco stalks in a sufficient quantity of water to make 

 the extract suitable, without further dilution, for immediate application 

 as a spray fluid against orchard and garden pests. The manurial 

 value of the spent stalks can be utihsed, and their use for illegal purpose^ 

 prevented by composting them with farmyard manure on the premises 

 where the extraction process is carried out. 



The obstacles that prevent the economic use of these stalks by 

 agriculturists and manufacturers in the United Kingdom are excise 

 restrictions and the patent rights of foreigners. During the fiscal 

 year 1915-16, 7,626,725 lb. of refuse tobacco stalks were abandoned 

 to the Crown, the present wholesale value of the available nicotine, 

 nitrogen, phosphoric acid and potash of which is approximately 

 £75,415. 



Hag AN (J.). Spraying Experiments. — Jl. Dept. Agric. & Tech. 

 Instruction for Ireland, Dublin, xviii, no. 2, 1918, pp. 186-188, 

 3 figs. [Received 7th December 1918.] 



This paper, an appendix to the preceding one, deals with the experi- 

 mental use of an extract made from refuse tobacco stalks against 

 green Capsid bugs, which during the past 8 or 9 years have occasioned 

 great loss to apple growers in Co. Armagh. 



Various methods of extraction were tested, namely, (1) steeping the 

 stalks three times in cold well-water, (2) steeping them twice in 

 cold well-water, the stalks, being pressed after the first steeping, 



(3) steeping the stalks once in cold well-water and pressing once, 



(4) steeping them three times in fresh cold well-water ; the total 

 amount of water used in each case being about 1 gal. to 1 lb. of 

 stalks. Of these, the last was the most satisfactory, as the quantity 

 of stalks and amount of water were such that a paraffin oil barrel 

 could be used advantageously, and the expensive and tedious process 

 of pressing was not involved. 



A block of apple trees all badly infested \nt\\ Capsid bugs and 

 larvae of Tortricids and the winter moth [Cheimatobia brumata] was 

 selected for spraying, lead arsenate (at the rate of 3 lb. to 40 gals, 

 extract) being added to make the spray effective against both biting 

 and sucking insects. The trees were sprayed immediately before the 

 flowers opened, and soon after the fruit had set. It was found that 

 the four different extracts gave results which were equally satisfactory, 

 and therefore three steepings of the tobacco stalks are not absolutely 

 essential. In another test, with trees very badly infested ^^^th Capsid 

 bugs, trees sprayed t^vice \\ith No. 4 extract showed about 2 per cent, 

 of fruit injured by the bugs, while unsprayed trees of similar varieties 

 showed about 75 per cent. 



