THE OLIVE tubercle: TYPE 393 



and Italy. Noack in Germany described this ash disease in 

 1893 and attributed it to bacteria, solely on the basis of his micro- 

 scopic examinations. Subsequently Vuillemin claimed it to be 

 the same as the olive tubercle with- 

 out, however, giving his reasons. 

 The writer first saw the ash disease, 

 in the vicinity of Vienna in 1913. It 

 persists from year to year on the 

 trunk and limbs, attacking chiefly 

 the bark, making rough cankerous 

 thickened patches as large as one's 

 hand or larger, but also stimulating 

 the growth of the wood so that the 

 cankered part of the trunk or branch 

 may be twice the diameter of the 





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1/ 



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Fig. sol Fig. 302. 



FiG. SOL — Olive tubercle. A detail from Fig. 300, showing secondary surface 

 infections. The primary inoculation was in 1910 with a pure culture isolated 

 from material collected by Florence Hedges at Portofino, Italy, in 1910. Photo- 

 graphed December 5, 1912, department of Agriculture hot-house. Tubercles 

 6 to 12 months old. One-half natural size. 



Fig. 302.^ — Cross-section of a young, cheesy olive tubercle (pure-culture in- 

 oculation), showing small brown bacterial areas with water-soaked borders. 



normal parts above and below it. The micro-organism present in 

 these ash cankers has been studied critically in my laboratory 

 by Nellie A. Brown and myself and is scarcely distinguishable 

 from the olive-tubercle organism morphologically and culturally 



