94 



JOURNAL AND PROCEEDINGS, 



to blackcaps in Missouri in the year 1887 from this fungus was esti- 

 mated at from ten to twelve per cent, of the entire crop. 



Fig. 29.— Baspberry Autbracnose. 



It first appears in the form of small purple spots scattered 

 around the lower parts of the canes. These soon rapidly increase 

 in size and spread from the lower portion of the canes upward, 

 giving them a scabby, pithy appearance, as shown in fig. 20. The 

 damage done by these blotches rarely extends to the pith, but the 

 greatest injury is done to the cambium layer, or the portion through 

 which the sap is conveyed in the process of growth, resulting very 

 much the same as if the cane had been girdled. As a result, the 

 leaves do not attain more than half the normal size, and the fruit, if 

 developed at all, does not reach its full development, but ripens pre- 

 maturely, or simply dries up and is worthless. If the canes are not 

 killed the first year, the continued action of the fungus on the leaves 

 and branches prevents the formation of fruit the succeeding year. 

 After the fungus has appeared upon the canes, the petioles of the 

 leaves are attacked in the form of purplish spots near their base. 

 Gradually the disease spreads throughout the whole framework of 

 the leaves, showing white blister-like spots. 



We omit any description of the botanical character of this fun- 

 gus, but simply remark that in overcoming it, a vigorous condition 

 of the plant is important, and any old plantations which are diseased 

 would be b'etter cleared out and burned. One experiment station 



