FIRE-BLIGHT OF APPLE, PEAR, ETC.: TECHNIC 377 



disease by insects. Avoid wounding the flowers in making the 

 inoculations. 



For varietal contrast, Seckel, Duchess, Douglas, Winter 

 Xelis or Kieffer (which blight slowly) may be compared with 

 Bartlett, Ho well, Flemish Beauty or Clapp's Favorite,! (which 

 blight rapidly). There is also a so-called "blight-proof" pear 

 derived from the Chinese Sand pear, which is not blight-proof 



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FIG. 291. Flagellate rods of Bacillus amylovorus. Stained by van Ermen- 

 gem's silver nitrate method. Isolation of 1908 from apple. X 1000. 



An isolation of 1915 from apple stained by Miss Bryan also^sho\ved peri- 

 trichiate flagella of the same type. 



(Fig. 296), and which may be tested. No entirely resistant 

 sorts are known to the writer but recently Reimer has discovered 

 several. These are stocks of Pyrus ussuriensis and other Asian 

 sorts (collected in China by Frank N. Meyer and by F. C. 

 Reimer). These are now being tested on a large scale in the 

 open field in several localities in the West by Reimer, and in the 

 East by the United States Department of Agriculture. O'Gara 



