EXPERIMENT STATION BULLETINS. 



443 



TABLE G. DUSTING AND SPRAYING BARTLETT PEARS^ MERRITT ORCHARD, 1920. 



Treatment 



Lime-sulphur, 1 — 50. 



Sulphur dust 



Sulphiu- dust 



Copper sulphate dust 

 Check 



Applications 



1, 2, 3, 4 

 1,2,3 



2,3,4 

 1, 2, 3, 4 

 



Total 



number 



fruits 



1170 



1264 

 781 



1249 

 285 



Scabby, 

 per cent 



10 

 15 

 22 

 23 



58 



Lime-sulphur spray gave better control of scab than the best dusted plot, 

 but in comparing the two plots the fact that the sulphur dust plot did not 

 receive the fourth application must be considered. The point of greatest 

 interest is that the sulphur dust plot receiving the ''pre-pink" application 

 showed 7 per cent less of scab than the plot not receiving the "pre-pink". 

 The copper sulphate dust did not give satisfactory results even with the full 

 schedule of four applications. 



In the Hawley orchard four average trees were selected from each plot for 

 "count" trees and the fruit from these trees sorted and counted to determine 

 the amount of scab present. The results are given in table 7. 



TABLE 7. DUSTING AND SI'RAYING BARTLETT PEARS, HAWLEY ORCHARD, 11)20. 



Treatment 



Lime-sulphur, 1 — 40. 



Sulphur dust 



Copper sulphate dust 

 Check 



Applications 



1, 2, 3, 4 



1, 2, .3, 4 



1, 2, 3, 4 







Total 



number 



fruits 



2947 

 4358 

 3806 

 2991 



Scabby, 

 per cent 



16 

 10 

 20 

 60 



In this orchard sulphur dust gave better results than lime-sulphur. Copper 

 sulphate dust failed here to give satisfactory results. 



In the Hawley orchard, sulphur dust gave better results than lime-sulphur 

 but in the Merritt orchard lime-sulphur gave more satisfactory results than 

 sulphur dust. This difference may be accounted for in part by the difference in 

 application in the two orchards. At the Hawley orchard the dusting was 

 usually more efficiently done than the spraying due to mechanical trouble 

 with the sprayer, while at the Merritt orchard the spraying was done in a 

 more satisfactory way due to atmospheric conditions which were unfavorable 

 to efficient dusting. 



Effect on foliage. Throughout the season, there was a marked difference 

 in the condition of the foliage of the several plots. The lime-sulphur spray 

 caused considerable foliage injury most of which developed after the calyx 

 application. This injury was not general over the trees but was limited to 

 small areas which probably received a heavier application or were closer to 

 the spray gun so that the material was driven against the leaves with greater 

 force. The foliage of all dusted plots was in excellent condition at all times. 



