MARKET DISEASES OF VEGETABLES. 37 



Small brown spots on the leaves, from which the dry cen- 

 ters often crack and fall out, are characteristic of this dis- 

 ease, which occurs on greenhouse lettuce. 



Ref. (2). 



MUSKMELON: (HONEYDEW AND CASABA): FRUIT SPOT. 



Cause: A fungus (Alternaria). 



On Honeydew melons, this disease appears first as small 

 water-soaked or chestnut-brown spots on the surface. As 

 these enlarge, they become more oval in shape and may 

 have wide water-soaked borders. Later the lesions become 

 more or less sunken and usually develop black centers. 

 Under humid conditions a velvety surface growth of mold is 

 produced on the lesions. This mold is at first gray, but soon 

 becomes dark greenish gray and later dark brown or almost 

 black. 



Continued development and coalescence of these lesions 

 lead to an extensive shallow rot of the rind accompanied by 

 a cracking of the surface. The affected tissue is at first very 

 soft and watery, later becoming yellowish and very dry, 

 tough, and leathery. The rot eventually penetrates through 

 the rind into the edible pulp below. 



The symptoms on the Casaba melon are essentially similar 

 to those on the Honeydew melon. On the striped Christmas 

 Casaba melon, the lesions are brown and less conspicuous 

 and the surface growth of mold is not common. 



Fruit spot lesions differ from those of anthracnose in the 

 absence of acervuli and in the moldy outgrowth usually 

 present. 



This disease was found very prevalent during the fall of 

 1918 on Colorado Honeydew melons, and on both the Ca- 

 saba and Christmas Casaba melons from Turlock, Cal. 



The source of infection is not known. The lesions appear 

 during transit and storage and become very conspicuous in 

 the market, not only detracting from the appearance of the 

 melons but also causing an objectionable surface rot. In 

 addition, the lesions also serve as points of entry for other 

 rot-producing organisms. 



No control measures are known. 



MUSKMELON: SUN-SCALD. 



(See Sun-Scald). 



MUSKMELON (CANTALOUPE): MISCELLANEOUS DISEASES. 

 BACTERIAL SOFT ROT. 



Cause : Bacteria. 



Wounds and fruit spot lesions may open the way for the 

 entrance of bacteria which cause a soft rot of the tissues. 

 This rot is very soft and mushy and the tissue appears water- 

 soaked. , 



FUSARIUM ROT. 



Cause: A fungus (Fusarium). 



