FIRE-BLIGHT OF APPLE, PEAR, ETC. I TYPE 



363 



bitten or punctured shoots. Sackett believes that we have 

 greatly underestimated the number of cases of hold-over blight, 

 especially on the smaller limbs and twigs, since in a total of 

 83 blighted pear twigs, examined by him in the winter and spring 

 of 1910 and 1911 in Colorado, 25 per cent contained living 

 bUght bacteria. These cultures were taken at the border line 

 joining sound and blighted tissues. On the contrary, working 



Fig. 279. — Fire-blight on apricot. A natural infection from an inoculated pear 

 tree in one of our hothouses. Photographed June 7, 1915. 



in Pennsylvania on pruned branches allowed to lie on the earth, 

 Fulton found that the bacteria were dead in nine-tenths of them 

 at the end of a week (35 branches tested). More tests should 

 be made in various localities. Here is a good opportunity for 

 useful experiments 



Secondary infections are very common during the growing 

 season, owing to the abundant and fluid nature of the bacterial 



