APPLE SPRAYING EXPERIMENTS IN I9I4. I93 



nice control of scab 'by the use of double strength arsenate of 

 lead in the calyx and subsequent applications where lime- 

 sulphur or bordteaux had been used in the pink." He then goes 

 on to state that certain factors, particularly of a local, climatic 

 vsature which influenced the results of the experimental trials 

 s'hould ibe taken into consideration in interpreting the figures 

 obtained. 



Dr. W. L. Howard of Missouri reported that in 1914 in the 

 case of an acre of Jonathan trees sprayed with arsenate of lead 

 alone the amount of cedar rust was reduced one-half.* There 

 was, however, a large amount of russeting of the fruit on this 

 plot which could not be accounted for except that it came from 

 bordeaux mixture which had been previously used in the spray 

 tank and not entirely removed. He suggests the possibility that 

 the scab control might be attributed to the same material. 



Professor Howard writing under date of April 20, 191 5, 

 says : "I have long felt that arsenate of lead possessed some 

 fungicidal value, particularly against such apple diseases as scab 

 and fly speck or sooty mold. Also, some of our fruit growers 

 in the Missouri peach belt feel that arsenate of lead contributes 

 materially toward the control of brown rot, aside from its value 

 as an insecticide in poisoning the curculio." 



In a previous publication the senior writer has called atten- 

 tion to the fact that other observers have also reported that 

 arsenate of lead alone, or in combination with lime-sulphur, 

 contributed either directly or indirectly to the control of certain 

 fungous diseases of the apple and the peach.f 



Arsenate of lead alone for calyx and later applications. The 

 very favorable results secured with arsenate of lead as a fungi- 

 cide for scab suggested a possible modification of spraying 

 methods by which the work might be materially simplified 

 without decreasing the efficiency. This plan was to use bor^ 

 deaux mixture or the stronger dilution lime-sulphur when the 

 blossom clusters were opening and the buds showing pink, but 

 for later applications to depend entirely upon double strength 



^Howard, W. L. Profits from Spraying Twenty-five Missouri Apple 

 Orchards in 1914. Mo. Agl. Exp. Sta. Bui. 124: 272. 1915. 



tMorse, W. J. Spraying Experiments and Studies on Certain Apple 

 Diseases in 1913. Maine Agl. Exp. Sta. Bui. 223 : 14. 1914. 



