226 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



In all of this work we have used the sulphur-arsenate dust, and during 

 the past two seasons a number of special dusts have been tested. Among 

 these were copper-lime dust, containing 20 percent, dehydrated copper 

 sulphate and two percent, copper carbonate ; copper-lime dust, containing 

 10 percent, dehydrated copper sulphate; copper-lime dust, containing 

 15 per cent, dehydrated copper sulphate and 15 percent. Venetian red; 

 commercial Bordeaux dust (11 percent, copper) with an equal amount 

 of hydrated lime; the preceding mixture with the addition of 2)4. per 

 cent, acacia; dry lime sulphur diluted with an equal amount of rye flour; 

 and sulphur dust containing 14 percent, dry lime sulphur. Approxi- 

 mately 10 per cent, of lead arsenate was included in each of the fore- 

 going mixtures. The Bordeaux dusts were used three seasons and the 

 copper-lim.e dusts have been tried during the past two seasons. 



Without definitely condemning any of the preceding mixtures it may 

 be noted that the materials which gave best results were the copper- 

 lime- Venetian red, and the sulphur-lime sulphur, with many points in 

 favor of the latter. We plan to test this mixture (sulphur 75, lime sul- 

 phur 15, lead arsenate 10) again during the coming season and hope 

 to try others of a somewhat similar character. We feel that the standard 

 sulphur-arsenate mixture is a good base because of its physical properties 

 and fungicidal action, but that some more active agent such as copper 

 or the dry lime sulphur may prove to be a desirable constituent. 



In all of our experimental work the 3-5-50 Bordeaux spray has been 

 the most effective fungicide and the lime sulphur spray next in value. 

 We believe that our data for the past two seasons were secured under 

 conditions which warrant close comparisons, and that the results are 

 reasonably reliable for the materials used. The equipment available 

 and the climatic relationships of the particular regions in question must 

 also be considered in connection with any data of this kind. 



Experiments in 1919 



Check Bordeaux Copper- Sulphur Lime 



Foliage data: spray lime dust dust sulphur spray 

 Leaf spot 



(Percent, of leaves diseased) ..78.1 52.9 61.5 60.8 35.0 

 Leaf spot 



{spots per infected leaf) 6.0 2.3 2.8 2.8 2.0 



Percent of scabby leaves 75.4 61.3 68.8 69.8 61.5 



Fruit Data: 



Percent, scabby fruit (total) 98.4 34.5 92.8 83.0 52.8 



Percent, light scab 9.1 17.9 29.0 37.6 23.6 



Experiments in 1920 



{Orchard No. i) 

 Foliage data: 



Percent, scabby leaves 80.4 1.8 60.1 23.2 23.3 



Fruit data: 



Percent, scabby fruit (total) 91.1 31.3 80.5 77.9 46.0 



Percent, light scab 20.0 17.8 35.3 34.3 28.3 



