MARKET DISEASES OF FRUITS AND VEGETABLES 41 



FRUIT SPOT 



OCCURRENCE, SYMPTOMS. AND EFFECTS 



The term ''fruit spot" or "flecking" is used to refer specifically to a 

 disease of bananas that is of minor importance in producing regions 

 but may develop to a serious extent during transportation and in the 

 ripening room. The disease has been reported from several countries 

 in the American Tropics and from various other parts of the world. 

 Because of its regular occurrence at certain seasons of the year and 

 its damaging effect on the appearance of the fruit when the spots are 

 numerous, the disease is regarded by importers as economically the 

 most important disease of its kind to which bananas are subject {72). 



The spots as they appear on green fruit in the field in Central 

 America (72) are circular or nearly so. reddish brown or black, and 

 surrounded by a green halo. The mature fruit spots, also called trans- 

 portation spots because they may develop on the fruit during transit 

 to market, are identical with the field spots in appearance. The ripen- 

 ing spots develop only after the fruit has begun to turn yellow or after 

 it has been held in the green condition for an undue length of time 

 under ripening conditions. Some of the spots may be similar to the 

 mature fruit spots except for the green halo ; others may develop as 

 irregular brown pits or tiny rust-colored specks. 



In the field, spots commonly occur on the inner faces of the fingers 

 and between fingers. On mature fruit the spots may develop over the 

 side of the bunch away from the banana plant but are usually most 

 abundant toward the tips of the fingers and especially on the upper 

 hand or hands as the bunch hangs on the tree. They also occur between 

 fingers and especially on the inner faces of the topmost hands as they 

 occur on the tree. If they develop in transit their location is about 

 the same as that just described. Spots on ripening fruit are most 

 abundant toward the tips of the fingers, especially on the inner faces 

 of the upper hands. 



The spotting is heaviest in the early part of November and increases 

 somewhat again in July, chiefly during transportation from the Trop- 

 ics. By the middle of August the increase during ripening becomes 

 serious, whereas the increase during transportation may be less 

 important. 



CAUSAL FACTOBS 



This type of fruit spot is apparently a nonparasitic or physiological 

 disease. Fungi sometimes occur in older or ruptured spots, but they 

 cannot be found in }~ounger ones. Field studies have not shown any 

 consistent relation between insects and fruit spot. The season of most 

 severe spotting coincides roughly with the season of heavy rainfall, 

 high humidity, and low evaporation, which is also the time of year 

 when concentrations of nitrates are low in the soil. These are the 

 conditions under which the activities of the banarra plant are lowest, 

 but what relation there may be between that fact and the development 

 of fruit spotting is not thoroughly understood. 



(See 72, 73.) 



CONTROL MEASURES 



Suggestions for avoiding loss from fruit spot include rejection of 

 medium or heavily spotted fruit in the Tropics and at port of discharge 



