342 



Edwin F. Hopkins 



not readily wet with water and consequently the water sprayed contained 

 but few conidia in suspension. This was demonstrated by a microscopical 

 examination of the drops on a slide sprayed with the suspension. Very 

 few spores were found, and hence the chances for infection were slight. 

 Since this method was unsatisfactory, an attempt was made to secure 

 infection by dusting; the conidia on with a camel's-hair brush. This 

 proved to be very successful, and abundant infection resulted, both on 

 dormant bulbs and on growing tulip plants. Plants inoculated in this 

 manner were sprayed with sterile water from an atomizer and kept 

 moist overnight. 



Results of inoculations 



The results obtained from inoculating dormant tulip bulbs with 

 mycelium are shown in table 1. From this table it is clear that the 

 dormant bulbs must be injured at the point of inoculation in order that 



TABLE 1. Results from Inoculating Dormant Tulip Bulbs with Mycelium 



* The arabic numerals represent cultures from domestic sources, and the roman numerals, those of 

 foreign origin. 



mycelium may infect them. Briefly stated, the entire sixteen of the 

 dormant bulbs which had been injured were infected by the inoculation, 

 whereas none of the eight uninjured bulbs were thus affected. On the 

 other hand, when ten bulbs were inoculated just after the flowers had 

 been cut, all became infected, although only five were previously injured. 



