Family Cucurbitaceae 223 



to black, erumpent, and finally almost superficial. 

 The necks of the perithecia are papillate. The 

 ascospores are cylindrical, two-celled, hyaline, and 

 slightly constricted at the septum (fig. 38 e). 



Control. Spraying with Bordeaux mixtures when 

 the plants are about half grown and before the disease 

 appears is recommended. Spraying should be con- 

 tinued so that the growing parts are kept covered 

 with the fungicide. 



ANTHRACNOSE, see WATERMELON, p. 240. 



LEAF BLIGHT 

 Caused by Alternaria brassica var. nigrescens Pegl. 



Leaf blight is a very destructive disease, often 

 ruining entire patches which otherwise looked very 

 promising. In some seasons, it is the greatest draw- 

 back to successful melon culture. 



Symptoms. The disease begins as small round 

 spots which gradually enlarge. These spots are dry, 

 brown in color and made up of concentric rings or 

 zones (fig. 38 f and g). Usually the spots are very 

 numerous and their presence causes the leaves to curl 

 and dry up prematurely, leaving bare vines and un- 

 protected fruit. As a result, the melons ripen early 

 and have an insipid taste, and are very poor shippers. 

 Leaf blight is most serious in fields where canta- 

 loupes are grown too long on the same field. 



Blight Resistant Cantaloupes. In selecting for 

 blight resistant cantaloupe (fig. 39 a- b), we must con- 



