PROCEEDINGS, 1915. 75 



To test the relative value of different poisons, a number of small 

 seedling trees in flower-pots were accordingly sprayed, both with and 

 without molasses. Lantern globes were placed over them and flies plac- 

 ed within while the tree was still wet. In this experiment, several other 

 interesting points were suggested which will give us assistance in out- 

 lining the spraying experiments for next year. Table XI gives us all the 

 data relative to this experiment. 



Arsenite of lime is the quickest acting poison, but unfortunately the 

 entire foliage of the trees was burnt. The two strengths of commercial 

 lead arsenate paste are next, the pound strength being a little the quicker; 

 whereas the home-made article is slower than either of them. Corona 

 Dry is even slower acting, which fact may partly account for the high 

 percentage of infestation for orchards No. 1 and 2 at Windsor, as they 

 were sprayed with the powder. Whether there is really this difference 

 between the different forms of lead arsenate, can only be decided by or- 

 chard results. 



More or less burning occurred when molasses was added to the other 

 poisons, but no scorching has ever been done to our sprayed orchards, 

 except in one case when arsenate of lime and molasses were used in one 

 spray, when about 30 per cent of the leaves were slightly burned. Furth- 

 er, it seems that the molasses is not altogether necessary in this spray as 

 the unsweetened poison killed just as quickly as the sweetened, indica- 

 ting that the molasses did not necessarily act as an attraction. And even 

 in the second series of experiments (Table No. XII) when new flies were 

 put into these same globes to note how soon they would succumb, when 

 the poison was dry, the addition of molasses does not seem to justify its 

 use. If this is really the case, our spray can be made much cheaper if only 

 the poison may be used alone. 



