The Botrytis Blight of Tulips 



345 



strongly infected and some showed aerial mycelium arising from the lesions. 

 On April 18, 1917, ten, clean, dormant bulbs were inoculated in the same 

 manner with conidia from a culture of strain B. XXVII. In several 

 days, nine of these showed numerous spots or streaks, varying in color 

 from yellow to brown, where the conidia had been sown. 



On March 30, 1917, at 5 p.m., four tulip leaves were dusted with conidia 

 from a pure culture and the following morning at nine o'clock small water- 

 soaked spots had appeared, a microscopical examination of the epidermis 

 of which showed that the conidia had germinated and had penetrated 

 the cuticle. On April 2 these spots showed a rusty color and were sur- 

 rounded by translucent, water-soaked areas. 



On April 1, 1917, at 4 p. m., three tulip plants in pots were inoculated 

 with conidia of strain B. XXVII and placed under a large bell glass. 

 On April 2, at 9 p. m., all had developed a considerable number of infections, 

 as shown by the large number of small, yellow spots. These spots later 

 become larger and of a somewhat reddish cast. About five days later 

 the plants were severely diseased and showed a mycelial growth on the 

 leaf surface, ^bout seven days thereafter conidia were formed. On 

 April 12 some sclerotia were noted in the leaf tissue. 



On April 13, 1917, eight tulip plants were inoculated with conidia of 

 strain B. XXVII and placed in a large moist chamber. On April 16 

 all showed numerous yellow-to-reddish spots on the leaves. A few similar 

 spots appeared on the stems. By April 18, the small spots had coalesced 

 and appeared as large, reddish lesions, some of which were covered with 

 abundant conidiophores. 



The inoculations with conidia are summarized in table 5. The plants 

 were not mechanically injured at the time of inoculation. 



TABLE 5. Results from Inoculating Uninjured Tulip Plants with Conidia 



