346 



Edwin F. Hopkins 



In using mycelium as inoculum on the leaves and the stems, the lesions, 

 after a short time, become as typical as those of the same age produced 

 in nature. In the beginning, however, although they show the char- 

 acteristic yellowing, they are not exactly like natural lesions, for they 

 assume the shape of the agar block used in the inoculation. As the infection 

 spreads, the region about the inoculum becomes water-soaked, then 

 depressed, and finally dried out. At the last stage, the lesion assumes 



a dull gray color and produces fluffy 

 mycelium and sometimes also a co- 

 nidial layer. The lesions tend to 

 elongate in the direction of the stem 

 and the leaf. If an inoculation is 

 made on the edge of a young leaf 

 near the tip, the peculiar twisting 

 described on page 323, under the 

 heading Symptoms, results. The 

 whole plant top may be involved as a 

 result of such an inoculation (fig. 42) . 

 On the dormant bulbs, also, the lesions 

 are typical (fig. 41) with a dark brown, 

 shiny surface. In using conidia as 

 inoculum, the lesions are typical from 

 the start and are essentially as de- 

 scribed on pages 319 to 328. 



With but few exceptions, when in- 

 fection was positive, the fungus in 

 these experiments was re-isolated in 

 pure culture by one of the isolation processes described under Methods, 

 and checked identically with the original culture. Usually the tissue- 

 planting method was the one employed. 



In order to determine the range of parasitism of this species, a con- 

 siderable number of experiments were made on both closely related and 

 distantly related plants to find out whether Botrytis Tulipae is able to 

 infect them. 



The general results of these experiments appear in table 6. Certain of 

 these, however, should be discussed more fully. 



Fig. 



40. MICROCONIDIA OF I 

 TULIPAE. X 600 



(Camera-lucida drawing) 



