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SCIENCE AND INDUSTRY. 
high pressure behind it, is the best for this mixture, which will 
kill caterpillars and similar soft-bodied chewing insects. Unlike 
the arsenates, nicotine does not remain long on the leaves as a 
poison, as it rapidly evaporates. 
(4) Bordeaux and Nicotine. 
This may prove a suitable mixture if used at the right time. It 
is not generally recommended, chiefly because some tobacco extracts 
have a solvent action on the copper constituents, and spray injury 
would soon result from the use of liquids containing soluble copper 
compounds. ‘The copper is also likely to precipitate the nicotine, 
but this may not matter. 
(5) Arsenate of Lead and Nicotine. 
This is a labour-saving combination, much used as an early 
spring wash against both biting and sucking insects, but it is not 
a fungicide. Each ingredient is more effective if used at its own 
time, nicotine being required often earlier in the spring. Further, 
the effect of nicotine is increased enormously when used with soft 
soap, and the strong, coarse spraying with nicotine is not the most 
suitable one with arsenate of lead, which requires it to be of the 
fine-mist type. As no fungicide is included, and as such would 
probably be essential, it would be more advantageous to separate 
these insecticides. Combine one with a fungicide, e.g., the lead 
arsenate and Bordeaux, both of which require the same kind of 
spraying, and the other (nicotine) with lime sulphur alone, or 
with soap alone with which it is very effective. 
(6) Arsenate of Lead and Nicotine and Lime Sulphur. 
(7) Arsenate of Lead ‘and Nicotine and Bordeauc. 
These combinations can be used if required, although nicotine is 
much more effective with soap, but soap is not recommended with 
lime sulphur. The spraying with arsenate of lead or Bordeaux is 
also of a different character to that advisable for nicotine. 
(8) Nicotine and Soap. 
This is a most useful and effective spray. Many preparations 
are on the market, and, as mentioned under No. 3, the purchaser 
should select only those makes which supply full information as to 
nicotine content, amount or weight of substance, freedom from 
pyridine, and methods for use. Many growers prefer to prepare 
‘their own extract. A good method is to make an extract of 2 Ibs. 
of tobacco stem or refuse in 2 gallons of water, boil up with 4 lb. 
soap, and make up to 5 gallons. The strength of nicotine is not 
known. Nicotine may be used on the most delicate plants. The 
strengths of solutions used are varied for different varieties of 
' insect, twice the strength being used for caterpillars as for aphids 
‘generally, also doubling the quantity of free soap, thus:— 
4-5 ozs. (95 per cent. pure) nicotine, 2-4 Ibs. soap for 100 
gallons water, for bugs. 
10-12 ozs. (95 per cent. pure) nicotine, 5-6 lbs. soap for 100 
gallons water, for caterpillars. 
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