38 U. S. DEPARTMENT OF AGRICULTURE. 



This is a rapidly progressing rot usually characterized 

 externally by a dense and profuse outgrowth of pinkish 

 white mold. The rotted tissue is rather dry, and the pink 

 mycelium may cause the entire rotted area to appear pinkish 

 in color. Other types of Fusarium rots may occur in the 

 field. These rots progress more rapidly than the rot caused 

 by Alternaria. 



GREEN MOLD ROT. 



Cause: A fungus (Cladosporium). 



This disease occurs very frequently on cantaloupes after 

 they have been in transit a long time. It is characterized 

 by a green, velvety fungous growth, which causes a slowly 

 progressing rot. 



MUSKMELON (CANTALOUPE AND HONEYDEW): 

 ANTHRACNOSE. 



(See Cucumber Anthracnose). 



MUSKMELON (HONEYDEW): BLACK MOLD ROT. 



Cause: A fungus (Alternaria). 



This is marked by a brown to black, velvety surface 

 growth of the fungus. The fungus usually invades tissue 

 killed by sun-scald and causes a rot of the underlying tissues. 

 This rot is also very common on watermelons affected by 

 sun-scald. 



ONION: BLACK MOLD ROT. 



Cause : A fungus (Sterigmatocystis niger) . 



Black mold is characterized by black, powdery masses on 

 or between the scales. When these masses occur between 

 the scales they have a tendency to follow the veins. 



Affected stock may show no symptoms other than the 

 presence of this black powder. At times sunken and dis- 

 colored areas are found underlying the powdery black 

 masses. Under dry conditions the affected tissue is papery 

 and brittle and sometimes highly colored. 



Although commonly called "smut," this disease should 

 not be confused with true smut. The latter is rarely found 

 on the market except on sets, and is marked by black, pow- 

 dery masses within the scale tissues. 



All varieties of onions are susceptible. The disease is 

 very common on California and Texas onions. Infection 

 occurs in the field, though the fungus continues to grow in 

 storage. 



As a rot, this disease under dry conditions usually is of 

 minor importance, but as a blemish it causes very serious 

 depreciation in value of the affected stock. Under moist 

 conditions the fungus may cause severe rotting. 



Since this disease does not progress very rapidly, affected 

 bulbs can probably be held for some time if they are kept 



