52 MAINE AGRICULTURAL EXPERIMENT STATION. 



The fungus associated with the cankers was easily isolated and 

 v/hile it is too early to make definite conclusions it appears to 

 be capable of producing the disease upon inoculation to healthy 

 limbs and twigs. These cankers as they occur in nature are 

 illustrated in Bulletin 223 of this Station. 



ORCHARD SPRAYING EXPERIMENTS IN I913, 



The fourth series of experiments in orchard spraying wete 

 carried out at Highmoor Farm during the summer of 19 13. 

 While the crop was very short on account of unfavorable 

 weather conditions at blossoming time and apple scab was not 

 so severe as was the case the previous season, some very inter- 

 esting results were secured. 



Perhaps the most important result from a practical stand- 

 point was from the use of arsenate of lead as a fungicide. 

 This is a well known and effective insecticide but its fungicidal 

 properties either have been overlooked or have not been fully 

 appreciated. The use of 4 pounds of arsenate of lead paste to 

 50 gallons of water in 1912 resulted in fruit as free from scab 

 as where lime-sulphur was applied with 2 pounds of arsenate 

 of lead paste to each 50 gallons. These results were fully 

 confirmed in 1913 with 2 pounds of dry, powdered arsenate 

 of lead instead of 4 pounds of the paste. Even one pound of 

 dry arsenate of lead to 50 gallons proved to be two-thirds as 

 efficient in controlling apple scab as lime-sulphur combined 

 with the same amount of poison. 



Arsenite of zinc used with lime-sulphur in 1912 resulted in 

 no injury but in 19 13 the same lot of material caused severe 

 leaf-spotting and considerable defoliation. The same effects 

 were obtained with 2 pounds of "Soluble Sulphur Compound" 

 and one pound of dry arsenate of lead in 50 gallons of water. 

 This last combination appeared to be quite efficient in scab con- 

 trol, however. "Atomic Sulphur," another proprietary com- 

 pound, also gave satisfactory results as a preventative of scab, 

 but caused no injury to fruit or foliage. 



The results secured in 1913 strengthened the conclusions 

 suggested by the work of the previous year that a dilution of 

 lime-sulphur 20 per cent stronger than standard could be used 

 on Ben Davis trees with little moire danger of injuring the 



