34 maine agricultural experiment station. 



Apple Spraying Experiments at Highmoor Farm. 



The season of 1914 marked the completion of the tifth year 

 of a series of apple spraying experiments carried on by the 

 Station at Highmoor Farm, the object in view being to improve 

 methods and mixtures in order to secure more efficient con- 

 trol of apple scab and other orchard diseases without adding to 

 the expense involved. Some very important and suggestive 

 practical results have already been obtained, particularly dur- 

 ing the past three years. 



One of the most striking results and to a certain extent an 

 unexpected result of the two previous seasons was the discovery 

 of the relatively high efficiency of arsenate of lead as a fungi- 

 cide when applied slightly in excess of the amount commonly 

 used as an insecticide. As yet an opportunity has not presented 

 itself where it has been possible to test the effect of arsenate of 

 lead alone under exceptionally severe conditions. Hence, a 

 plot sprayed with this without the addition of any other fungi- 

 cide was included last season and will be repeated each year 

 till a season occurs where the weather conditions are excep- 

 tionally favorable to scab development. 



Arsenate of lead is well and favorably known and widely used 

 for spraying apple trees as an insecticide in combating codling 

 and brown-tail moths and kindred pests of the orchard. In 

 recent years it has been known to have some fungicidal value, 

 but apparently no one has considered this to be of much impor- 

 tance for when used in connection with bordeaux mixture, lime- 

 sulphur, or other recognized fungicides in spraying experiments, 

 it has been customary to assign to the latter all beneficial results 

 secured in the control of parasitic fungi. Hence, the observa- 

 tions made at Highmoor Farm with regard to the fungicidal 

 value of arsenate of lead may be looked upon as discoveries of 

 considerable practical value. 



In 1912, a plot of trees sprayed only with arsenate of lead at 

 the rate of four pounds of the paste form to 50 gallons of water 

 showed better scab control than where standard dilution lime- 

 sulphur and two pounds of arsenate of lead paste has been 

 applied and even better than where bordeaux mixture and the 

 smaller amount of the insecticide was used. No unsprayed 

 check plot was available that year. ^ 



