Small Fruits 



103 



leaves develop unequally, 

 often with inrolled edges. 

 Upon the lower surface very 

 small spots about 1 mm. in 

 diameter are produced, from 

 which the diseased tissue 

 often falls. In the older 

 diseased spots the spore- 

 bearing acervuli are just 

 visible to the naked eye. 



Occasionally, an incipient 

 attack may escape observa- 

 tion during the first and 

 second years, and even well 

 into the third year. Then, 

 with prospect of a good 

 yield, the berries shrivel on 

 the stems and later many 

 plants die. More often the 

 disease remains moderately 

 injurious from year to year, 

 weakening the plants and 

 diminishing the yield. 



In localities subject to 

 this disease, it is best to 

 rotate crops so as to avoid 

 keeping raspberries or 

 blackberries more than 

 three years on the same 

 soil, and to set out only 

 healthy plants. When the 

 disease appears, cut out and 

 burn diseased parts immedi- 

 ately after picking. Spray- 

 ing with lime-sulfur is effective. Use three applications, 

 (1) before the leaves appear, 1-20, (2) when the shoots are 

 six inches high, 1-50, (3) just before blossoming. 



Fig. 51. — Anthracnose on black 

 raspberry, showing typical fis- 

 sures. After Burkholder. 



