THE BLACKHEAD FIEEWOEM OF CKAITBERRY. 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 soaf 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 cranberrj^ spraying. It could not be mixed, 

 however, with hard loater or combined with Bordeaux mixture or 

 any other alkaline solutions; and since it takes 4^ parts of the 

 nicotine oleate to equal in nicotine content 2^ parts of the 40 per cent 

 nicotine solution, about ticice as much nicotine oleate as Jfi fer 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 XVI) 

 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 farmer 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 badl}^ eaten and nearly 

 all the berries destroyed b}' 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 



