MAINE AGRICULTURAL EXPERIMENT STATION. I914. 35 



In 191 3, an unsprayed check plot was added and powdered, 

 dry arsenate of lead substituted for the paste. Two plots were 

 sprayed with arsenate of lead alone, one with two and another 

 with one pound of the powder to 50 gallons of water or equiva- 

 lent to about four and two pounds of the paste form, respect- 

 ively. Nearly 39 per cent of the apples on the unsprayed plot 

 Vv-ere scabby. Almost perfect scab control was secured with 

 bordeaux mixture, lime-sulphur and the larger amount of 

 arsenate of lead used alone — the efficiency being in the order 

 named. Attention should be called to the fact that one pound 

 of dry arsenate of lead was added to each 50 gallons of the 

 bordeaux mixture and lime-sulphur, also that where this smaller 

 amount of arsenate of lead was used alone the amount of scab 

 was reduced from nearly 39 per cent to less than 16 per cent. 

 Hence, it is more than a possibihty that when the insecticide is 

 added to bordeaux mixture or lime-sulphur, it may contribute 

 materially to the fungicidal effect of the combined spray. 



In 191 3 there was considerable russeting of the fruit. Much 

 of this as indicated by the condition of the apples on the un- 

 sprayed check plot was due to natural conditions, but this rus- 

 seting was largely increased by the action of some of the sprays. 

 This increase of russeting on the lime-sulphur and bordeaux 

 plots was about 1 1 and 40 per cent, respectively, while, where 

 the two pounds of dry arsenate of lead was used alone in 50 

 gallons of water, it was actually less than on the check plot. 



The results secured in 1912 and 191 3 were sufficiently encour- 

 aging to warrant a repetition of this part of the experiment, but 

 omitting the smaller amount of arsenate of lead used alone. 

 Also the results of the previous season suggested the alluring 

 possibility that, except for the "pink spray," arsenate of lead 

 used somewhat in excess of the usual amounts might be 

 depended upon to prevent apple scab as well as control certain 

 of the more important insect enemies of the orchard, thus elimi- 

 nating a considerable part of the labor and expense of orchard 

 spraying. 



Accordingly, in 1 9 14, in addition to spraying a plot with 

 arsenate of lead alone, used at the rate of two pounds of the 

 dry powder to 50 gallons of water, one plot was sprayed the 

 first time with a 3-3-50 bordeaux mixture, plus one pound of 

 the dry lead arsenate and later with two pounds of the arsenate 



