THE FUNGI WHICH CAUSE PLANT DISEASE 51 



Bacillus 1.2-2.5 x 0.5-0.7 /i, variable, actively motile in young 

 cultures. Capsulated, no spores, peritrichiate. No gelatine 

 liquefaction. On agar thin, smooth, milk-white. No gas, aerobic 

 or facultative anaerobic. Milk not curdled. T. D. P. 43°, 10 min. 



This pathogen was first reported by E. F. Smith without de- 

 scription in 1893 "' and more fully in 1895.1^" It is found filling 

 the vessels of cucurbits, (musk melons and cucumbers) affected 

 with wilt. Smith produced the disease artificially by puncture 

 inoculations on the blades of leaves with the white sticky fluid 

 from infected veins. The inoculated plants showed symptoms of 

 wilt after four days and sixteen days later the ducts of the vine 

 were found to be plugged with bacteria. The organism was then 

 isolated from this artificially infected plant. The cultures thus 

 obtained were carried by transfers over winter and in December 

 were used successfully to 

 infect cucumber plants. 

 Control plants were never 

 diseased. The ready 

 growth of the organism in 

 the vessels is attributed to 

 the alkalinity of the latter; 

 the failure to grow in the 

 parenchyma is attributed 

 to its acidity. •a'J»» ' 5^' . »^^ 



B. uvae Cug. & Mac. is C-*'*\""^**« f^' tj^'*'^^*/ 



reported as causing injury jj,* '^ uj ^ ^ ^' '*^'' • ^v 

 to young grape clusters.!" ^' r ^i.t\ ' ^*'*'!^--V* ' 



It is perhaps identical with *- * ^ -*'• •^' *"' ' '''"* 



B. ampelopsorae. 



B. vulgatus (Flligge) 

 Mig. This organism is 



found as small thick rods ^^ ^_^ tracheiphilus. 'Ifter Smith, 

 with rounded ends, or is 

 often paired or in chains of four; sporiferous. Gelatine colonies 

 round, liquefaction rapid. Growth on agar dirty-white. 



It has been shown capable of causing rot of various vegetables. *" 



B. zeae Burr, is the name appUed to a bacillus isolated from 

 diseased com plants by Burrill in 1887-1889."'' ^^* It is often 



