Ll. Lloyd 



91 



an acre of plants. The work was therefore more thoroughly done than 

 would be possible in a trade nursery. In s|)ite of this, very poor control 

 was kept, as only a small proportion of the larvae present were discovered 

 at any one examination. Many matured and pupated, so that the 

 summer brood was as large as the spring one. Much fruit was bitten 

 and many stems were eaten through. The adjoining house was first 

 examined on May 1, a fortnight after the plants were put out, and 79 

 larvae were counted to each hundred plants. These were not removed 

 and a few days later the house was sprayed with arsenate of lead, the 

 operation occupying one hour, and 10 gallons of diluted spray being 

 used. Two days later it was again examined and 26 larvae were counted 



Diagram IV, 



Contrasting the control effected by hand-picking and spraying 



with arsenate of lead . 



to each hundred plants. Ten days after this another count gave four 

 larvae to the hundred plants. It then received its second spraying as 

 before and no more larvae were seen until June 21, and from that time 

 on, till the comparison was stopped at the end of July, very few were 

 seen, though later in the season they became more numerous. 



Diagram IV shows the results of this experiment in a graphical 

 manner. The continuous line represents the number of larvae found to 

 the 100 sprayed plants in each of the 10 examinations made. The dotted 

 line shows the number removed from each 100 plants in the unsprayed 

 house on approximately the same dates. The hand-picking during these 

 three months occupied over 70 hours and was inefficient. The spraying 



