MUSTARD BEETLE. 99 



Some consideration is, I understand, to be given to trial with the 

 Potato-spraying mixture known as BouiUie Bordelaise, but I should 

 myself be afraid that it might so injure the outside of the Mus- 

 tard leaves (by slightly hardening the skin) as to be prejudicial to 

 growth. 



The above notes are merely an endeavour to bring forward some of 

 the points useful for consideration in dealing with Mustard Beetles, 

 whether the PIuBilon, or other kinds which infest the plants ; and in any 

 of the details which I happen to have knowledge of myself, it would 

 only be a pleasure to me to give any information in my power. 

 Amongst these are observations kindly made for me by Dr. J. A. 

 Voelcker, Consulting Chemist of our Royal Agricultural Society, 

 regarding mixture of Paris-green with soft-soap ; and also observations 

 given me by Prof. F. Shutt, Chemist to the Dominion Experimental 

 Farms of Canada, relatively to mixture of Paris-green with various 

 kinds of soap, and also the extremely important observation relatively 

 to non-absorption of Paris-green, that in a large quantity of sprayed 

 Apples, subjected to analysis which would show the presence of even 

 as small an amount as one fifty -thousandtli part of a (jrain of arsenic, it 

 was proved that they were free. 



The main matter, however, in the preventive work appears to me 

 to be how to (/row the Mustard crop so that preventive measures may be 

 brought to bear on it when it is past its first young condition. If we 

 could but do this, I believe the clearance of the infestation would be 

 easily practicable. 



S*^ 



