Fungous Disi;asi;s or Plants, I^i a( h \'i;i.lows M7 



Mention is made of fifteen species of Exoasct/s, all of which produce 

 characteristic hypertrophies. Seven of these species also cause hcxfuhaeti 

 or witchbroonis, and tlicse peculiar t^rowths arc also induced by various 

 Uredineae, notably by the aecidium {Peridermium pint) of Coleosporiuin 

 seneciofj/s, and by Aeciditnn {Periderniitnn) ehit'ntiini. 



The black-knot of the plum and cherry, Plnwr'ight'ui morhosa, is said to 

 occur only in North America, but the author thinks it may be introduced 

 into Europe at any time. This is quite likely and the wonder is that it 

 should not hxive occurred before, owing to the fact that it is found in all 

 our species of Prunus and is very destructive in many parts of the eastern 

 United States. . . . 



In this review Smith did not mention Luigi Savastano's recent 

 assertion that Bacillus oleae had been found in Italy to cause the 

 disease known as tuberculosis of the olive. Preliminary pronounce- 

 ments on the organism's pathogenic nature had been made in 1886 

 and 1887." Either complete and positive proof, tantamount to 

 that available in pear and apple twig blight, had not come to 

 Smith's attention or he still indulged some skepticism. News of 

 new scientific discoveries in Europe were still slow in reaching 

 America. Smith's growing interest in plant bacteriology was still 

 mainly a reading interest. His account of this discovery was later 

 as follows: ^* 



In 1886 Archangeli described the olive tubercle, giving the name Bac- 

 terium oleae to something observed in it but without what we should now 

 [1920] consider to be a proper description, i. e., it was named from the 

 microscope, without cultures or proofs of its infectiousness by inoculation, 

 and with the statement that it probably had nothing to do with the disease, 

 which was ascribed by him to other causes. Savastano's inoculation experi- 

 ments (1887-1889), repeated and confirmed by [Fridiano] Cavara, first 

 proved the olive tubercle to be due to bacteria, but neither of these men 

 described the organism sufficiently. Savastano called his cultures Bacillus 

 oleae-tuberculosis, but, following Trevisan, systematic writers generally 

 have spoken of Bacillus oleae (Arch.) Trevisan as the cause of the olive 

 tubercle. 



Smith, during the 1880's, like most other American botanists, 



^^ Nosologic vegetale — Lcs maladies de I'olivier et la tubcrculose en particulier, 

 Comptes rendus 103: 1144; Tuberculosi, iperplasie et tumori dell' olivo, Ann. R. 

 Sc. sup. PortJci 5, 4th fasc, 1887. 



Proof of the bacillus was presented in, II bacillo della tubercolosi dell' olivo, 

 Rend, della R. Accad. del Lince't., 92, 1889. 



^*' An introduction to bacterial diseases of plants, 389-411, at p. 394, Phila. and 

 London, W. B. Saunders Co., 1920. A whole chapter of this book is given to 

 " The Olive Tubercle " or olive knot. 



