68 GRASSHOPPERS AND OTHER INJURIOUS INSECTS OF 1911 AND 1912. 



ORCHARD SPRAYING IN 1911 AND 1912. 



The results of this work are shown in detail by many tables, too 

 voluminous to be included in a report of this nature. We append 

 surnmary of results both for 1911 and 1912, as reported by Assistant 

 Entomologist Ruggles, who had charge of these experiments. The 

 co-operative orchard spraying both in 1911 and 1912 was for sev- 

 eral reasons a failure in so far as any reliable results were ob- 

 tained. 



Summary of Apple Orchard Spraying in 1911. 



"The flat orchard in the spraying experiment consists of eight 

 rows of trees with fifty or sixty large bearing trees in each row. 

 As said before, this orchard does not lend itself to a good spraying 

 experiment, because the varieties are not placed in a satisfactory 

 manner. The orchard was divided into five plots, each containing 

 as nearly as possible the same variety of apples. One plot was left 

 as a control or check. Three sprayings were given to each sprayed 

 plot, — the first at the time the buds were bursting, the second just 

 after the blossoms had fallen, and the third two weeks later. 



On one plot three pounds of arsenate of lead was added to fifty 

 gallons of 1-30 Commercial Lime Sulphur. Another plot was 

 sprayed with three pounds of arsenate of lead added to the 4-5-50 

 Bordeaux mixture. Another plot was sprayed with two pounds of 

 arsenate of lead in fifty gallons of iron sulphide. Another plot was 

 sprayed with two pounds of arsenate of lead in fifty gallons of self- 

 boiled lime sulphur. 



In the control plot or check there was only 47.6 per cent of per- 

 fect fruit, — that is, saleable fruit. There were 17 per cent marked 

 with curculio and 6 per cent injured by codling moth. The rest 

 were diseased. 



When two pounds of arsenate of lead were used the curculio 

 injury was reduced from 17.1 per cent to 5.2 per cent in one case, 

 and in another case to 5.6 per cent. When three pounds of arsenate 

 of lead was used the curculio injury was reduced still more, — to 2.7 

 per cent in one case and 3 per cent in another. This shows that 

 two pounds of arsenate of lead is an excellent insecticide against 

 curculio, reducing the injury about 12 per cent, and three pounds of 

 arsenate of lead will reduce the injury about 14 per cent. It is 



