Some Important Orchard Plant Lice 17 



Thus it appears that even \\hen used with soap, which seems 

 to give to it the maximum kilhng strength for aphis, i part of 

 the nicotine to 500 parts of water was required to give a com- 

 plete kill. 



This suggested a numljer of points that needed clearing up, 

 such as : 



1. To what extent in comparison with other treatments 

 does winter-strength lime-sulfur effect a control when 

 applied during dormancy and before the eggs have 

 hatched ? 



2. To wdiat extent will winter-strength lime-sulfur ap- 

 plied at the green bud stage just after the lice hatch 

 effect a control? 



3. To what extent is the combination of winter-strength 

 lime-sulfur and 40 ])er cent nicotine at the rate of 500 

 to I superior to a combination at the rate of i.ooo to i ? 



4. To what extent would a winter-strength lime-sulfur 

 treatment before the lice hatch, followed by an extra 

 treatment of nicotine and soap just after the lice hatch, 

 prove eft'ective? This point was considered because of 

 the fact that in 191 5 the hatching of the rosy aphis 

 was thought to have occurred after the buds opened. 



5. To what extent would Scalecide (for which claims 

 have been made ) serve as a control ? 



In 19 1 6 experiments were planned to answer these questions. 

 They were located on the farm of Mr. John Barclay, of Cran- 

 bury. Mr. Barclay made all the applications according to 

 schedule, and the quality of the spray coatings given by him 

 could not be bettered. The trees were seven years old and very 

 thrifty. 



The plan of the experiments follows: 



