34 PROTECTION OF PLANTS — 1922-23 



It is scarcely necessary to state that if lime-sulphur is used for this spray 

 it need not be stronger than about 1 gallons to 35 gallons of water and no 

 poison would ordinarily be required. 



If du^t is used instead of liquid I think I should be guided largely by the 

 weather, I should dust first whenever wet weather threatened after the buds 

 had burst and leaflets were beginning to show and then give another applica- 

 tion when the blossom-bud clusters were appearing. 



DUSTING VERSUS SPRAYING. 

 By G. E. Sanders, Deloro, Ont. 



The question of dusting versus spraying is one that continues to be dis- 

 cussed at every Horticultural Meeting just as twenty years ago no Entomo- 

 logical Meeting was complete without a discussion as to the relative merits 

 of Paris green and lead arsenate. Twenty years ago, there were certain places 

 where Paris green was superior to other poisons then on the market. So with 

 liquid spraying today. 



I have probably conducted as many small plot tests of liquid and dust 

 spraying experiments as any man in this room and have visited almost as 

 many fruit sections and orchards as any of you during the past three years 

 and I want to say to you that when experimental plots, say even acre plots, 

 begin to run within five per cent of each other in insect or fungus control, 

 then, it is beyond the power of the experimenter to say from data obtained 

 from his own plots which material is going to give the cleanest fruit when 

 placed in the farmers' hands. 



In a number of reports I have published the data ga^thered by Prof. H. H. 

 Whetzel of Cornell which gave a summary of 4 years' dusting in New York, 

 Nova Scotia, Illinois and Michigan, a total of 16 years' experiments, comparing 

 the fungicidal value of sulphur du^t and lime sulphur spray. By a singular 

 coincidence, this data averaged the same to one-tenth of one per cent in apple 

 scab control. This data was all secured by professional experimenters, some 

 of whom had good dusting machines and some poor; some had good spraying 

 machines and some poor ones. On the whole, I have found that expenmenters 

 spray more efficiently than the average farmer while they do not dust nearly 

 as efficiently. They usually do their dusting on the same days as they do 

 their spraying regardless of weather conditions, and often, owing to the inde- 

 finite relations between the experimenter and the orchard owner's hired man , 



