1910 .j PUBLIC DOCUxMENT — No. 31. 55 



SPRAYING EXPERIMENTS WITH CALCIUM 



BENZOATE. 



BY G. E. STONE. 



Calciiini benzoate has been recommended by manufacturers 

 and dealers for a few years past as being a fungicide of some 

 value, and samples of this substance have frequently been sent 

 to us for trial by the manufacturers, with directions as to its 

 proper use. We have previously tested sodium benzoate, an 

 allied compound, on potatoes, and the results are reported else- 

 where. ^ 



It was desired that a test be made of this substance for the 

 control of plum rot (Afonilia), the claim having been made that 

 it would completely control the rot. If true, the calcium ben- 

 zoate would prove of inestimable value to the fruit grower, and 

 would find a ready market. 



In testing the material we selected half a dozen plum trees, 

 leaving checks for comparison. The trees, which were laden 

 with fruit and had always been susceptible to the rot, were given 

 a very thorough spraying with the calcium benzoate, at the rate 

 of 2 pounds to 50 gallons of water. The spray covered the 

 foliage and fruit very thoroughly, and was applied at a favor- 

 able time to control any rot which might subsequently appear. 

 As the season was very dry, and no rains occurred during the 

 period of experiment, none of the substance was washed off. 



Later in the season considerable rot was observed on both 

 the sprayed and unsprayed trees, and a thorough examination 

 showed absolutely no difference in the sprayed and unsprayed 

 fruit as regards infection. We regard the experiment, there- 

 fore, as being purely negative in its results. 



> Annual Eeport Hatch Experiment Station, 1908, p. 128. 



