The Anthracnose Disease of the Raspberry 179 



after the fruiting season is good cultural practice, but from the stand- 

 point of checking the disease it is beneficial only in obtaining better 

 aeration. Thorough cultivation, especially the eradication of weeds, like- 

 wise is advantageous, or any measure that has a tendency to keep the 

 canes free from persistent moisture. 



SPRAYING 



Numerous attempts have been made to control anthracnose by spraying, 

 but the results in most cases have been questionable. Since he found 

 the raspberry disease so similar to anthracnose of the grape, Scribner 

 (1888) recommended spraying with iron sulfate when the plants were in 

 a dormant condition, and using bordeaux mixture if subsequent appli- 

 cations were necessary. 



Paddock (1897) conducted spraying experiments in a black raspberry 

 plantation for three years with doubtful results. At least he came to 

 the conclusion that spraying was not a profitable operation, but the 

 data given by him may be interpreted otherwise. His experiments 

 briefly are as. follows: 



The first three rows in the raspberry plantation were sprayed when 

 dormant with copper sulfate, using three pounds to eleven gallons of water; 

 the next three rows were treated with a saturated solution of iron sulfate 

 in water; the last three rows were left unsp rayed. This plan was repeated 

 five times. The two treated series were then followed with five appli- 

 cations of bordeaux mixture. The yields of berries are given on the three 

 series for three years. The spraying was begun in 1894, and therefore 

 the yield in 1895 was the first on treated canes. The yield in that year 

 was much increased over that of the preceding year. For the treated 

 rows there was an increase of 171 per cent and 148 per cent, respectively, 

 while for the check row the increase was only 39 per cent. In 1896 there 

 was not such a great difference in the yields, but the infection, even on 

 the check rows, was very slight. Paddock compared his data one year 

 at a time and did not take into consideration the fact that the spraying 

 of the canes one season affected the yield the following year. Therefore, 

 with the present interpretation of the results obtained by Paddock, there 

 seems to be a pronounced indication that spraying would be profitable, 

 at least in years when the anthracnose infection is severe. 



Rees (191 5) claims that blackberry anthracnose in the northwestern 

 United States can be controlled b}^ spraying. This, however, is hardly 

 comparable with spraying for the control of the same disease on the 

 raspberry. The benefit derived from treating the blackberry plant is in 

 preventing berry infection, while on the raspberry the fruit is never 

 infected. 



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