26 



THE HOP APHIS IX THE PACIFIC EEGION. 



Table VI represents the work done in Oregon by Mr. H. N. Ord 

 and is in part a repetition of the results recorded in Table V. It 

 also contains data upon tobacco waste, which appears very satisfac- 

 tory and very cheap. If the decoction is allowed to boil or the tobacco 

 happens to be low in nicotine, the spray will not be effective, and the 

 vines will have to be resp rayed. 



If this material be used each tankful should be tested upon some 

 aphides and a record of efficiency kept. It is for these reasons not so 

 satisfactory as a material containing a known quantity of insecticide. 



Xicotinc-sulphate formulas for 100-gallon lots. 



Ounces. 



Nicotine sulphate, 1 to 1.000 13 



Nicotine sulphate, 1 to 2.000 6£ 



Nicotine sulphate, 1 to 2,500 5£ 



Nicotine sulphate, 1 to 3.000 4£ 



The formula " 4-100/' given for flour paste, means 4 gallons of 

 flour paste (made according to directions) to each 100 gallons of spray. 

 This paste contains 1 pound of flour in each gallon, so that there 

 would be 4 pounds of flour (in the form of paste) in each 100 gallons 

 of spray. 



The formula " 4-100," when referring to whale-oil soap, means 4 

 pounds of whale-oil soap to 100 gallons of spray. 



Flour paste had proved to be a most efficient, cheap, and convenient 

 spreader for the lime-sulphur solutions. 1 Some experiments were 

 conducted during 1912 with this material in combination with nico- 

 tine sulphate against the hop aphis. Table VII gives some of the 

 results obtained with this mixture. 



Table VII. — Experiments in the control of the hop aphis by sprays of nicotine sulphate 



and flour paste. 



Formula. 



Nicotine sulphate, 1-2,000; flour paste, 4-100 



Nicotine sulphate, 1-2.500; flour paste, 4-100 



Nicotine sulphate, 1-3,000; flour paste, 4-100 



Do 



Nicotine sulphate, 1-3,500; flour paste, 4-100 

 Nicotine sulphate, 1-4,000; flour paste, 4-100 



Number 





of 



Per cent 



aphides 



killed. 



present. 





627 



100 



611 



100 



1,668 



99 



148 



99 



308 



100 



271 



% 



Cos^ ner 



100 

 gallons. 



?0.71 

 .60 

 .50 

 .50 

 .45 

 40 



From the results noted in the preceding tables it is evident that 

 nicotine sulphate is effective in dilutions as high as 1-3,500, and that 

 flour paste, 4-100, is an effective spreader for this material. The 

 nicotine sulphate, 1-4,000, was not quite so effective, and it was also 

 observed that its action was so slow that the sprayed aphides were 

 able to deposit young on the leaves, thus reinfesting the hopvines. 



1 See Bulletin No. 117 and Circular No 166 of this bureau. 



