2 BULLETIN 924, TJ. S. DEPARTMENT OF AGRICULTURE. 



The economic importance of this blemish is chiefly due to the 

 financial loss which the grower sustains as a result of the lowered 

 market value of the affected fruit, which is rendered unsightly and 

 unattractive. However, tear-stained fruit seems to possess flavor 

 and keeping qualities essentially equal to fruit which is free from 

 these markings. 



REVIEW OF THE LITERATURE. 



A careful survey of the literature reveals the fact that very little 

 has been published on the subject. The cause of tear-stain was 

 investigated and first reported on. by Rolfs (7), 1 who is quoted as 

 follows : 



This peculiar form of russeting manifests itself by streaks running over the fruit 

 from the side that hangs uppermost to the point which is nearest the ground. The 

 cause of this peculiar form of russeting is that somewhere above the fruit a twig 

 occurs which has been infested by the fungus 2 and which contains the hold-over 

 spores. Whenever sufficient rain or dew occurs to cause a dripping from the disease- 

 infected twig on to the fruit, the disseminating spores are liberated from the twig 

 and carried with the rain or dew over the epidermis of the fruit. Many of the spores 

 are left along in different places, and these produce sufficient irritation to the epi- 

 dermis to cause russeting along in streaks; hence we have the peculiar form of tear 

 staining or tear streaks. 



Again in 1911 Rolfs (8) discussed the subject as follows: 



Russeting and tear streaking can nearly always be traced back for their beginning 

 to a small dead spur or sprig. The fungus 2 lives in the dead spur or sprig. Water 

 from rains and moisture following heavy dews collect in drops on these sprigs or 

 spurs and the drops when they fall cany with them numerous fungous spores. These 

 spores come in contact with the epidermis of the fruits and germinate, causing 

 minute lesions on the epidermis, too small for complete infection and the production 

 of anthracnose. 



This explanation as presented by Rolfs, to the effect that Col- 

 letotrichum gloeosporioides is the responsible agent, seems to have 

 been accepted by several investigators at various times, among 

 them Fawcett (2-5), Stevens (9), Stevenson (10), and Matz (6). 



On the other hand, Earle and Rogers (1) recognized in the Isle 

 of Pines two types of russeting or tear staining said to be easily 

 distinguishable, the one attributed to rust mites and the other 

 thought to be caused by a fungus. In discussing wither-tip they 

 make the following statement: 



One of the serious troubles attributed to the wither-tip fungus in Florida is that 

 water washing down from infected twigs will cause the serious discoloration of the 

 fruit known as tear streaking. The discoloration is often confused with the work of 

 the rust mite, though it is easily distinguished. It frequently occurs here and can 

 be always traced to some dead twig, but we are still uncertain whether it is due to the 

 secretions of the wither-tip fungus or the Diplodia. 



'■ The serial numbers in parentheses refer to "Literature cited " at the end of this bulletin. 

 * Colletotrichum gloeosporioic'is, mentioned in the context. 



