264 BULLETIN 94. 



from a culture on vetch stems was photographed with an amplifi- 

 cation of loo diameters and is shown in Fig. 53, Plate VI, lower 

 figure. The preparation was mounted in water and the conidia 

 which were so numerous that they would have clouded the prepar- 

 ation were mostly washed out. Quite a number, however, remain- 

 ed in the preparation, and show as minute oblong dark spots over 

 the field of the photomicrograph . The fruiting stool is composed 

 of numerous branched sporophores closely compacted together. 



CANKER IN CUCUMBERS. 



What is sometimes called canker in cucumbers has occurred dur- 

 ing the two past winters in the horticultural houses of Cornell 

 University. The appearance is that of a larger and deep ulcer in 

 the stem at the surface of the ground. It occurs on plants of 

 considerable size, on stems from 5 cm. to i cm. or more in diame- 

 ter, the vines of which are several meters long. The ulcer has a 

 dull brown color, the color of the external portion depending to 

 some extent on the amount of soil which becomes worked into it. 

 The tissues for some depth are soft and more or less putrid, 

 dependent on the stage of the disease. It may advance so far as 

 to cause the stem to rot off entirely, when of course the plant dies. 

 In other cases the plant may not be ultimately killed but the 

 ulcer has affected so deeply the vascular tissues as to interfere 

 greatly with certain physiological functions of the plant. As the 

 disease becomes serious the plants take on a sickly yellowish 

 green color and become more or less limp. It soon soon runs its 

 course, ending in death. During the month of December, 1894, 

 sections of a diseased stem were placed in water and kept as 

 described above for the seedling fungus, and in twenty-four hours 

 a profuse growth of an Artotrogus, supposed to be the common 

 A. debaryanus was developed. The species was at that time not 

 accurately determined, and at the present writing there is none of 

 the disease in the houses. The trouble is invited by keeping the 

 soil around the stems in a too wet condition, just such conditions 

 as favor the development of the seedling fungus. It is quite pos- 

 sible that another fungus to be described in a later paragraph may 

 also have something to do with the etiology of the trouble. 



