MICHIGAN ACADEMY OF SCIENCE. 89 



Humphrey^ noted the disease in Massachusetts as affecting the 

 leaves in the season of 1892, no other part of the plant being at- 

 tacked. The leaves are described as showing translucent, watery 

 spots, the fungus growing within the tissue and seinding out 

 through the stoniata, hyphal branches on which the conidia were 

 produced. 



Ho describes the spore production as follows: — "A highly compli- 

 cated mass of spore threads, consisting of the successive acropetal 

 production of sprout buds from the originally terminal joints so 

 that there are formed chains of successively smaller and smaller 

 cells." 



He simply described the organism without recommending any 

 control beyond the suggestion of spraying. 



In 1896°, Aderhold noted the fungus near Breslau in Germany 

 and identified it as Cladosporium cuoumeriiuim Ell. and Arth. He 

 inferred its parasitism from inoculation experiments with field ma- 

 terial and found it prevalent both in the gardens and under the 

 glass. 



He endeavored to connect it with Sporidesmmm mucosum found 

 on other cucurbits but did not find sufficient ground to warrant 

 such a belief. 



Since that time the literature shows little work on the disease, 

 the few references being confined to mere mention of its occurrence. 

 There is no record of special experiments for its control except 

 the work of Frank mentioned above. I have it verbally from Mr. 

 W. A. Orton. however, that the Department of Agriculture con- 

 ducted spraying experiments along this line in Michigan about 

 1905 with little success. 



SYMPTOMS ON THE HOST. 



On the fruit the disease appears as a very slightly sunken, 

 water-soaked spot, usually accompanied by a small drop of gummy 

 exudation. As the fungus progresses this spot becomes more 

 sunken and is covered with a smooth, velvety, olive-black coating 

 of spores and conidiophores. These spots are seldom more than 

 2-5 mm. in diameter, although several will often coale&ce to form 

 larger patches. 



If cut through in cross section the fruit shows a shallow depres- 

 sion of about .5-3 mm. in depth. This depression is underlaid by 

 a slight cavity in the flesh but the lesion never extends deeply into 

 the fruit. Where the fruit is allowed to mature however, these 



5. Humphrey, J. E. 10th Rept. Mass. Exp. Sta. 1892, p. 227. 



6. Aderhold. R. Zeitschrf. f. Pflanzenkr. VI, 1896. p. 72. 



