April, '11] LOHRENz: woolly aphis 163 



sprayed. Just next to the sprayed plat there was a seedhng with a 

 large colony of the Aphis. The whole plat, including this infested 

 tree, was sprayed again with a 10 per cent emulsion. 



About the 20th of October these seedlings were taken up and exam- 

 ined. The results are given below in tabulated form: 



Second Series 



On August 10 another series of plats was marked off on the same 

 block of apple seedlings, with the numbers 13-27, Nos. 28 and 29 

 were added later. The ground was too wet for successful spraying, 

 and because of continuous rains further work had to be postponed 

 until fairer weather set in. 



As copper sulphate was recommended by some for insects affecting 

 roots it was tried on plats Nos. 24-27, but without results. 



On September 10, although the ground was yet quite wet, a 10 

 per cent kerosene emulsion was used on plats Nos. 13-16, 21 and 22. 

 The Aphis were present in great abundance, both on the tops and 

 on the roots. 



Examination on September 24 and October 1 showed that the 10 

 per cent emulsion under those conditions had only a limited effect on 

 the Aphis. 



On October 1 the ground was in fair condition and plats Nos. 14, 

 15, 21, and 23 were sprayed again mth the 10 per cent emulsion. 



About the 20th of October these seedlings were lifted and examined; 

 the results are shown below in tabulated form. 



Third Series 



Plats Nos. 16, 18, 19, 20, 28, and 29 were used in the third series. 



The solution used was kerosene emulsion of 15 per cent strength 

 and was applied "October 1. 



These seedlings were lifted along with the others about October 20, 

 and the results are tabulated below. 



All of the above plats, Nos. 1-29, contained only those places 

 which were very badly infested with Aphis. They extended from 

 six inches to five feet along the rows of the seedlings. 



