MARKET DISEASES OF FRUITS AND VEGETABLES 5 



Most of the market decay has been attributed to the common soft rot 

 organism (Erwinia carotovora (Jones) Holland). Two other bac- 

 terial pathogens (Pseudomonas cichorii (D. B. Swing.) Stapp and 

 Ps. intybi (D. B. Swing.) Stapp), first described on chicory in this 

 country, have since been reported as causing leaf rots of endive in 

 Germany. 



( See also Spinach, Bacterial Soft Hot, p. 16. ) 



(See 67, 130, 133.) 



Leaf Discolorations 



Leaf discolorations of considerable market importance have been 

 observed on both escarole and endive. Symptoms differ somewhat 

 on the two types of plant. The cause of the leaf trouble is not known 

 for either plant. 



The symptoms as observed on escarole are primarily drying, brown- 

 ing, and partial blackening of the tip of the outer leaves (pi. 2, B 

 and C). Ordinarily the outermost four to six whorls of leaves are 

 found affected on the marketed leaf heads. The completely blanched 

 center leaves have never been found affected (pi. 2, C). The injury 

 usually extends % to 1 inch from the leaf tip. The edges of the leaf 

 blade are also frequently affected for an inch or two. As affected 

 tissues dry they turn dark, curl up, become brittle, and are usually 

 rather sharply set off from the healthy tissues. This leaf discolora- 

 tion is found frequently in Florida escarole and occasionally affects 

 a high percentage of the leaf heads. 



On endive there has been found a brownish discoloration of the 

 fringed edges and tips of the blanched heart leaves. Generally neither 

 the green tips of the partially blanched leaves nor the outer leaves 

 are affected. Associated with the killing of the marginal tissues is the 

 development of tiny reddish-brown spots or streaks on the fleshy 

 midribs (pi. 2, A). The discolored streaks range from one-thirty- 

 second to one-sixteenth inch in length and are very numerous. This 

 injury has been observed in California endive. In many instances a 

 very high percentage of the leaf heads are affected. The limited evi- 

 dence available indicates that this leaf discoloration originates during 

 transit in refrigerated shipments made to distant markets. 



Watery Soft Rot 

 (Sclerotinia sclerotiorum (Lib.) DBy. and 8. minor Jagger) 

 (See Lettuce, Watery Soft Eot, p. 11.) 



GLOBE ARTICHOKES 



Globe artichokes for the market are the immature flower heads 

 (buds) of Cynara scolymus L., a herbaceous perennial plant. The 

 fleshy flower base or receptacle, the young flowers, and the tender base 

 of the bracts or scales together make up the edible portion of the 

 buds. 



The globe artichoke should not be confused with the Jerusalem- 

 artichoke (Helianthus tuberosus L.), which is grown for its under- 

 ground tubers. 



