POTATO DISEASE'S 'TN 1907. 29I 



Plot 8 was dusted with 6 pounds Leggett's Blight Dust No. 

 2 per acre. 



Plot 10 was dusted with 6 pounds Bowker's Dry Boxal per 

 acre. 



Plot 12 was sprayed with 10 pounds Bowker's Boxal Paste 

 per acre. 



To apply the dust sprays a horse power cart of the type known 

 as the "Beetle" was used. To secure uniform applications and 

 to avoid changing the regulator on the machine for each plot, 

 more or less prepared or ground lime was thoroughly mixed 

 with the dust used on each plot and applied with it, i. e., the 

 dust application was made up to equal volume on each plot with 

 lime. The lime simply acted as a dilutant and in no way inter- 

 fered with the action of the dust spray. The Boxal paste was 

 mixed thoroughly in the keg at each application and then the 

 required quantity weighed out. With a small quantity of water 

 this was stirred in a pail till all lumps had disappeared and then 

 thoroughly mixed and agitated with the necessary amount of 

 water in the spray tank. 



The Boxal preparations claim to serve as insecticides as well 

 as fungicides, therefore no paris green was used with these and 

 none was necessary. On the other plots from one to one and 

 one-half pounds per acre of paris green was used at each appli- 

 cation as long as necessary, mixing it with the dust or wet bor- 

 deaux as the case might be. 



The field was visited nearly every week during the season, 

 and at no time did over 10 days pass without observations as 

 to the condition of the foliage. Early blight (Altemaria solani) 

 was practically absent except for a small amount late in the 

 season, and practically all of the damage to the foliage resulted 

 from attacks of the late blight (Phytophthora infestans). The 

 record for the condition of the foliage after blight was first 

 observed is as follows : 



further: * * * "The sulphate and benzoate exchange places forming 2 

 other materials viz. sodium sulphate and copper benzoate. Now it is 

 the copper benzoate that combines all the virtue of the spray, it being 

 infinitely less soluble than the original chemicals while combining the 

 germicidal and fungicidal value. Copper benzoate is very slow to wash 

 off with the rain and practically the only successive sprayings necessary 

 are those required to protect new growth." 



