THE CANADIAN ENTOMOLOGIST 277 



A REVIEW OF THE WORK ON THE POISONED BAIT 



SPRAY, DRY METHOD AND MIXED TREATMENT 



OF CONTROLLING FRUIT FLIES (TRYPETID.F:). 



BY HENRY H. P. SEVERIN, PH.D., MILWAUKEE, WIS. 



(Continued from p. 246). 



Olive Fly (Dacus olece Rossi.). 



After the Italian entomologists, De Cillis and Berlese, had 

 demonstrated the effectiveness of the poisoned bait spray to con- 

 trol the olive fly, Chapelle (2 and 3) and Ruby, of France, carried 

 on a series of similar spiaying experiments to combat this same 

 pest, and confirmed the results obtained in Italy. The work of 

 the Italian entomologists with the dry method and mixed treat- 

 ment of controlling the olive fly was also tested by the French 

 scientists. 



In 1907 two of Dr. De Cillis' formulas (Table II) were used 

 by the French scientists. As some of the ingredients of these 

 formulas were rather expensive, Dr. Berlese began to experiment 

 along more economical lines, and in 1908 one of his formulas 

 (Table II) was tested. The following table shows the formulas 

 which were used in France from 1907-1909: 



TABLE II. 



1907 1907 190S 1909 



Molasses (45 to 50% sugar) 65 40 98 90 



Honey 31 40 



Sodium arsenate 2 2 2 2 



Glycerine 2 



Water IS .. 10 



In 1907 the formulas were diluted in the proportion of 10 

 kilogrammes of the" solution to 100 liters of water, but in the next 

 two years 20 kilogrammes of the solution to 100 liters of water was 

 used. The 20% concentration gave the diluted solution a syrupy 

 consistency and consequently a better adherence to the leaves. 



The number of applications of the spray, dose per tree and 

 cost, including labour, was as follows: 



1907 190S 1909 



Number of applications of spray 5-6 3-4 6 



Dose per tree 5-1 .3-. 5 .5 liters 



Cost of treatment per tree 4-9 1 1/5-1 3/5 4 cents 



The first application of the spray was made about fifteen days 

 before the egg-laying period began. The bait was uniformly ap- 



August, 1914. 



