COMBINED SPRAYS FOR CONTROLLING INSECT PESTS. 
the soluble form. Such a combination is then safe to use imme- 
diately. The addition of lime to the neutral type should not be 
necessary, but it does no. harm, and if the arsenic is not up to 
standard it may be the means of preventing injurious arsenic 
compounds going into solution. ; 
These figures must be taken as a guide only, as the exact strength 
of the lime sulphur solution is not given and the lead arsenates vary 
so much. 
(2) Lead Arsenate + Bordeaua. 
This is a safe and useful mixture. On account of the excess of 
lime even acid lead arsenate or Paris green can be advantageously 
mixed with Bordeaux. In order to reduce the amount of copper 
sulphate, and to keep the lime in excess, the formula 5-5-50 has 
become very popular (5 lbs. of copper sulphate, 5 Ibs. quicklime, 
and 50 gallons of water, instead of the old formula 6-4-50). It is 
a good combination for apple scab and caterpillars. 
(3) Nicotine + Lime Sulphur. 
Alkalies are unlikely to affect free nicotine in extracts. Nicotine 
sulphate, which is the principal compound of the alkaloid nicotine 
in the various spray substances, would be decomposed by alkalies, 
and the nicotine set free. It would be just as active in this form. 
The extracts on the market are very variable in composition, 
strength, &c. There is much confusion over the percentage of 
nicotine (alkaloid), or its salts, such as nicotine sulphate. We 
have local preparations, some of which give the percentage of 
nicotine and some do not. In all cases the grower should insist 
on being supplied with such information. This could readily be 
supplied if preparations that did not give full information were 
consistently rejected on that account. It is very handy to know 
that all one has to do is to boil a few ounces of soap with a gallon 
of water, add the nicotine, and make up to so many gallons. If the 
percentage of nicotine were known, the resulting spray could be 
compared with products and results elsewhere—e.g., “Black Leaf 
40,” an American preparation, has been proved to contain the 
reputed 40 per cent. of nicotine sulphate. In some experiments 
similar results could only be obtained by certain growers using 
1 part in 800 of water, 1 part in 500 water, and 1 part in 400 
water. It was found that the soap, or soap powder, as used by 
some, was at fault. In many Australian preparations far too little 
soap is used. Nicotine is very much more effective when used with 
sufficient free soap. A well-known local extract contains 2 per 
cent. nicotine, and the 16-oz. tin (containing 4-oz. nicotine) is 
made up to 5 gallons of spray, using 4:o0zs. yellow soap. This 
corresponds. with a well-known English formula of 6 ozs. of nico- 
tine (95 per cent. pure) to 100 gallons of water and 5 lbs. of soap. ' 
Another local preparation does-not state the percentage of nico- 
tine, and uses ounces, instead of pounds, of soap. Nicotine is a 
very effective and rapid killer of sucking insects, also of many - 
biting insects that it may hit. A coarse, penetrating spray, with 
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