CONTROL OF THE HOP APHIS. 



25 



show the results of these experiments and give the cost of the mate- 

 rials per 100 gallons of spray: 



Table V. — Results of spraying experiments for the hop aphis, with costs of materials 



per 100 gallons of spray. 



Experi- 

 ment 

 No. 



Materials used. 



Pressure. 



Number 



of 

 aphides. 



Per cent 

 killed. 



Date 

 sprayed. 



Date 

 counted. 



Cost per 

 100 gal- 

 lons. 







Pounds. 













1 



Nicotine sulphate, 1 to 3,000 



80-100 



1,227 



99.9 



June 15 



June 17 



$0. 416 



2 



Nicotine sulphate, 1 to 2,000 



.. 80-100 



1,005 



97.8 



June 13 



...do 



.62 



3 



Nicotine sulphate, 1 to 3,000; 

 whale-oil soap, 4 to 100. 



80-100 



3,089 



99.2 



June 14 



...do 



.80 



4 



Nicotine sulphate, 1 to 3,000; 

 cresol soap, 1 to 300. 



80-100 



1,990 



95 



June 15 



...do 



.83 



5 



do 



80-100 



3,474 



84 



...do 



...do 



.83 



6 



Blackleaf tobacco, 1 to 75 



80-100 

 80-100 



1.810 

 2,320 



94 



97 



...do 

 ...do 



...do 



...do 



.86 



7 



Nicotine sulphate, 1 to 2,000; 



1.04 





cresol soap, 1 to 300. 















8 



Blackleaf tobacco, 1 to 60 



80-100 



2,590 



99.8 



...do 



...do 



1.08 



9 



Nicotine sulphate, 1 to 1,000 



80-100 



654 



98.2 



June 13 



...do 



1.25 



10 



Nicotine sulphate, 1 to 2,000; lye- 

 resin soaps. 



80-100 



2,225 



99.1 



June 15 



...do 



1.37 



11 



Nicotine sulphate, 1 to 1,000; 

 whale-oil soap, 4 to 100. 



80-100 



2,512 



99.4 



June 14 



...do 



1.42 



12 



Nicotine sulphate, 1 to 1,000; 



80-100 



2,780 



99 



June 15 



...do 



1.67 





cresol soap, 1 to 300. 















INEFFECTIVE MATERIALS. 



13 

 14 



Limesulphate, 36° Baume, 1 to 86. 

 Cresol soap, 1 to 300 



80-100 



1,950 



14 



June 16 



June 19 



80-100 



129 







June 13 



June 16 



.24 

 .42 



From the data in Table V it is evident that all the experiments 

 except Nos. 5, 13, and 14 were quite satisfactory and that Nos. 1, 

 2, 3, and 4 were the cheapest materials to use. It was found that 

 the nicotine sulphate without soap did not spread very readily and 

 that the good results obtained were due to the very careful applica- 

 tion. Either flour paste or soap should always be used with the nico- 

 tine solutions. 



Table VI. — Spraying experiments conducted in Oregon against the hop aphis during 1911. 





Materials used. 



Tobacco waste, 25 pounds to 100 

 gallons water. 



Tobacco waste, 27J pounds to 100 

 gallons water. 



Nicotine sulphate, 1 to 2.000 



Nicotine sulphate, 1 to 2,000; whale- 

 oil soap, 5 to 100 



Nicotine sulphate, 1 to 1,000 



Nicotine sulphate, 1 to 2,000; whale- 

 oil soap, 5 pounds to 100 gallons 

 water ■ 



Nicotine sulphate, 1 to 750 



Pressure. 



Number 



of 

 aphides. 



Pounds. 

 100 



213 



100 



253 



100 



695 



100 

 100 



529 

 73 



100 

 100 



491 

 130 



Per cent 

 killed. 



100 

 100 



89 



98 

 100 



Date 

 sprayed. 



Aug. 22 



...do 



Aug. 21 



...do 



...do 



Date 

 counted. 



Aug. 25 



Aug. 24 



Aug. 23 



...do 



...do 



9* ...do i. ..do 



97 ; Aug. 22 ; Aug. 25 



Cost per 



100 

 gallons. 



JO. 18 



.20 



.62 



.845 

 1.25 



1.475 

 1.66 



