-8 



AGRICULTURE OF MAINE. 



VALUE OF ARSENATE OF LEAD IN LIME-SULPHUR FOR CONTROL OF 



SCAB. 



Arsenate of lead added to the lime-sulphur spray is con- 

 sidered to greatly increase its fungicidal value. A series of 

 tests to get additional information as to the actual gain from 

 its use for the control of scab was undertaken. Arsenate of 

 lead is necessary for the control of insects and for this reason 

 cannot be left out of our sprays. Its value as a fungicide has 

 not, however, shown up very great in these experiments. 



All plots were sprayed at the same time. May 25, June 20 and 

 July 6, with the same strength lime-sulphur, 1.009 specific 

 gravity, for the first spray and 1.008 for the next two applica- 

 tions. This test was conducted at Falmouth. 



Arsenate of Lead to 100 Gallons 



OF LiME-St'LPHUR. 



o 

 m 



tit? 



£6? 



7i lbs. neutral lead 



5 ' 



5 " acid lead . . . 

 2i " neutral lead 



2 " dry lead 



Lime-sulphur only . . 

 No spray 



no fruit. 



1.63 

 no fruit. 

 .67 

 1.37 

 34.56 



COMMERCIAL CONCENTRATE VERSUS HOME BOILED CONCENTRATE 



LIME-SULPHUR. 



Eight different experiments were conducted with home boiled 

 concentrate and commercial concentrate lime-sulphur applied 

 at the same strength, 1.008, with arsenate of lead added. One 

 application was made before the blossoms opened and two after. 

 The following is a summary of the results. 



% Scab. 



Commercial concentrate 1.38 



Home boiled concentrate .94 



No spray 5^-^ 



WHICH SPRAY IS THE MOST IMPORTANT. 



In order to determine if possible the relative importance for 

 scab control, of the different sprays, a series of tests were made 

 at Berwick. Lime-sulphur arsenate of the same strength was 



