122 Maine Agricultural Experiment Station. 1918. 



This view is strengthened by the fact that on plot 5 where the 

 acid arsenate was used with lime-sulphur about 23 per cent more 

 scab was obtained than there was on plot 7 where the "T. P." 

 arsenate was used in like manner. 



LIME-SULPHUR WILLI XO ARSENICAL ADDED. 



The marked fungicidal value of arsenate of lead when used 

 alone suggested that it might contribute materially to the fungi- 

 cidal qualities exhibited by the combined lime-sulphur and ar- 

 senate of lead spray. To secure data on this point in 191 7 plot 

 8, Table. III. was included in the experiments. The fact that 

 about 52.5 per cent of scabby apples were obtained on this plot 

 and only about 44.5 on plot 7 where the "T. P." arsenate was 

 added to the same strength lime-sulphur might indicate that 

 there is something in this hypothesis were it not for the fact 

 that over 67.5 of scabby fruit was obtained on plot 5 where the 

 acid arsenate was used in like manner. It will also be seen 

 on comparing the figures obtained on plots 1 and 2 with those 

 for plot 8 that lime-sulphur, standard strength used alone was 

 decidedly more efficient than double strength arsenate of lead, 

 both forms, used alone. Xo definite conclusions shouM be 

 drawn from this single trial, however. 



MODIFIED SPRAYIXG PROGRAM. 



The modified spraying program such as was carried out on 

 plot 5 in 1916, Table I. and plot 3 in 191 7, Table III, in which 

 lime-sulphur 20 per cent stronger than standard is used for the 

 pink-bud spray, followed by double strergth arsenate of lead 

 for the two later applications, has now been tested for 4 con- 

 secutive seasons, in comparison with plots sprayed all 3 times 

 with standard lime-sulphur and arsenate of lead, and double 

 strength arsenate of lead alone, respectively. In addition plots 

 1 and 5 of 191 6 were duplicated on a large scale in the orchard 

 known as Ben Davis Xo. 1, see Table II. 



The results obtained in scab control in 1916 on the experi- 

 mental plots and in the large orchard were very uniform for 

 each kind of treatment. Plot 1 and the east half of Ben Davis 

 Xo. 1, sprayed according to the standard program, produced 



