PEAR DISEASES 333 



of those varieties already mentioned. The Kieffer shows con- 

 siderable resistance in some parts of the country. 



Pear-scab occurs practically everywhere the fruit is grown. 

 It was found in Belgium in 1832, but was not reported as doing 

 great damage until 1875. Elsewhere in Europe scab prevails 

 commonly on the pear. In the United States outbreaks occur 

 in New England, the Middle West and along the Pacific Coast. 

 It was particularly destructive in 1906 over the country gen- 

 erally ; in 1898 it was epiphytotic in Ohio ; in 1902, 1910, 1912 

 and 1915 it was unusually prevalent in New York; while it 

 prevailed extensively in California in 1904, 1905 and 1906. 



Symptoms. 



The disease is found on the fruit, leaves and twigs. On the 

 fruit (Fig. 92) the spots are at first olivaceous, velvety and 



FIG. 92. Pear-scab. 



circular in form. Later in the season this velvety aspect be- 

 comes corky and the skin is cracked, sometimes in a T-shape 

 fashion (Fig. 92). At times growth of the young fruit is halted, 

 and so when such pears are mature they are considerably 

 distorted. Affected fruit may drop when the size of a cherry. 



