EXPERIMENT STATION BULLETINS. 643 



termined. It is believed that these hyphae (as a base) become asso- 

 ciated with the hyaline hyphae to form the pycnidial wall. It might be 

 mentioned that all media become strongly browned immediately after 

 the pycnidia begin to form. The source and nature of this browning 

 must remain for future investigation. 



Growth on Media: 



Macroscopic Cultural Observation : 



The following media were used : Cornmeal agar, nutrient glucose agar, 

 prune juice agar, tomato agar, nutrient saccharose agar, nutrient broth, 

 bean pods, potato plugs, tomato leaves, tomato stems, cornmeal and 

 rice. 



Spores from pure culture were inoculated into three tubes of double 

 distilled water so that a microscopic examination gave about 36 spores 

 in a loop. One loop of spore suspension was introduced in each tube 

 of media. This experiment was carried on in triplicate, one tube being 

 sealed with sealing wax,'' three tubes of each medium making up one 

 series. Five of these series were arranged. These were allowed to grow 

 at room temperature for 48 hours ; Series 1 was placed in the greenhouse 

 under the plants that were severely affected with the disease (Approx- 

 imately room temperature) ; Series 2 in the ice box, (Approximately 

 12°) ; Series 3 in 371/2°; Series 4 (room temperature, about 21° C.) on 

 shelf in the window of the laboratory; Series 5 (room temperature) dif- 

 fused light. 



In the accompanying table the growth on different media for 3, 6, 8, 

 10, 12 and 18 daj^s respectively is described for Series 1. Series 3 made 

 no growth whatever at 37 %° and after ten days was placed at room 

 temperature but did not revive. All the other series were so nearly 

 identical that it is needless to differentiate between them. The organ- 

 ism made no growth on bean pods. Tomato agar and cornmeal agar 

 were found to be the best media. In the former the growth simulated 

 more closely than in any other medium, the growth on the leaf. The ex- 

 cessive stroma production found in other media was absent. The pyc- 

 nidia were separate and distinct, the development almost identical as to 

 the time necessary for pycnidia production after inoculation. The to- 

 mato agar seemed to inhibit the growth of molds and bacteria when 

 plates were poured from field material. The use of the autoclaved to- 

 mato leaf was also very satisfactory^, although here no definite spots or 

 colonies were formed, the growth being diffuse. 



The following table gives the result of this experiment: 



"Reported on page 23. 



