THE BLACKHEAD FIREWORM OF CRANBERRY. 25 
Two and one-half parts of a 40 per cent nicotine solution unites 
with If parts of commercial oleic acid or red oil. Four and one- 
fourth parts of this soap will then contain 1 part of nicotine or will 
equal 2^ parts of the 40 per cent nicotine solution. 
It will thus be seen that nicotine oleate is a nicotine soap made 
from a fatty acid and nicotine ; as such it has the spreading properties 
of a soap and in addition it is a contact insecticide which can gener- 
ally be used in place of the ordinary 40 per cent nicotine sulphate 
and soap solution for cranberry spraying. It could not be mixed, 
however, with hard water or combined with Bordeaux mixture or 
an}^ other alkaline solutions; and since it takes 4^ parts of the 
nicotine oleate to equal in nicotine content 2-J parts of the 40 per cent 
nicotine solution, about twice as much nicotine oleate as Jfi per cent 
nicotine sulphate had to be used to equal one part of the latter. 
A spray material of this character, which has combined in it 
both soap and nicotine, would greatly facilitate the control of the 
fireworm, if not materially reduce the cost, wherever its use is prac- 
ticable. Solutions of the strengths used seemed to spread equally 
well over the cranberry foliage. As shown in Table 3, it was used 
at the rate of 1 part to 300 parts of water, 1 to 400, and 1 to 500, 
about equal, respectively, to 1 to 600, 1 to 800, and 1 to 1,000 of the 
40 per cent nicotine sulphate formulas. Both three and four appli- 
cations were made of each strength. The largest percentage of 
fruit free from fireworm injury seemed to be obtained where nicotine 
oleate was used at the rate of 1 to 500 and applied four times. There 
is very little difference between the results of this plat (plat XYI) 
and those secured on plat XIII where nicotine oleate 1 to 400 was 
applied three times. This is partly explained by the fact that the 
fireworm infestation was more thinly scattered over the former plat 
than over the latter. The results where nicotine oleate was used 
at the rate of 1 to 300, while apparently very satisfactory, are not 
so good, considering all factors, as where it was used at the rate 
of 1 to 400. 
Arsenate of Lead. 
As in 1918, arsenate of lead proved to be of little or no value in 
the control of the fireworm, the foliage being badly eaten and nearly 
all the berries destroyed by the worms, even where four applications 
were made with the addition of soap. 
Wetting Agents or " Spreaders." 
That the presence in the spray liquid of some material like soap, 
which will make it wet or spread over the smooth, waxy foliage of; 
the cranberry, seems to make considerable difference in the control 
