GRASSHOPPERS AND OTHER INJURIOUS INSECTS OF 1911 AND 1912. 69 



probable that with four pounds of arsenate of lead to the spraying 

 material the percentage of curculio injury would have been still 

 smaller, but it is doubtful whether it would pay to use the extra 

 pound of arsenate of lead. It is a question also whether it is advis- 

 able to use three pounds instead of two pounds of arsenate of lead, 

 there being really only 2 per cent of difference in favor of three 

 pounds. 



The tables also show, as mentioned in previous reports, that the 

 codling moth is not the primary pest of apples in this part of the 

 state. Even in the checked plots only 6 per cent were injured by 

 codling moth. It will be noted, however, that spraying reduced this 

 to 2 per cent. 



About 13,000 apples were counted in compiling these tables. 



Work of 1912. 



In spraying the apples in the flat orchard in 1912, the orchard 

 M^as divided into three plots. One plot was a control. Three rows 

 were sprayed with iron sulphide, and three rows, 6, 7, and 8, were 

 sprayed with Commercial Lime Sulhpur plus three pounds of arsen- 

 ate of lead. The data of times of spraying are appended. 



The summary of the tables show rather interesting results. We 

 started out in the season intending to use commercial lime sulphur 

 plus arsenate of lead, and iron sulphide plus the arsenate of lead. 

 After the commercial lime sulphur plots were sprayed, the arsenate 

 of lead ran out and rather than to wait for the material to come 

 from the cities, we started to spray the plot rows 3, 4, and 5, with 

 the iron sulphide alone. Throughout the season, these rows, 3, 4, 

 and 5, were sprayed only with iron sulphide. On the control plots, 

 we obtained only 40 per cent of perfect fruit; 25 per cent were 

 marked with curculio, and nearly 7 per cent were marked with cod- 

 ling moth. The rest were diseased. In the plots sprayed with iron 

 sulphide alone, and with the commercial lime sulphur plus the 

 arsenate of lead, the results are surprisingly similar. For instance, 

 the perfect fruit with the iron sulphide was 63 per cent; with the 

 commercial lime sulphur and arsenate of lead, it was 64 per cent. 

 With the iron sulphide alone, the curculio injury was reduced to a 

 little over 8 per cent. With the commercial lime sulphur and 

 arsenate of lead, the reduction was almost to 8 per cent. With 

 the codling moth, with the iron sulphide alone, the reduction was 

 about one-half that of the control, namely, 31/2 per cent. 



