CHAPTER XIII 



PREVENTION OF FRUIT ROTS 



The rots affecting fruit stored or in transit are mostly caused 

 by saprophytic or weakly parasitic fungi. As fruit approaches 

 ripeness the natural resistance associated with tissue in a state 

 of activity is reduced, and the mechanical protection of rind 

 or cuticle has to be mainly depended upon to prevent the invasion 

 of the tissues. 



The fungi most concerned in decay of fruits ordinarily shipped 

 in the West Indies are the Penicilliums (blue moulds) Diplodias, 

 and, on pineapples, Thielaviopsis. It has been repeatedly 

 demonstrated that the occurrence of blue moulds on citrus 

 fruits — the best known type of fruit rot — depends entirely on 

 the presence of injuries, in which either the surface of the rind 

 is broken by scratches, cracks or punctures, or the cells of the 

 rind are burst by injuries of the nature of bruises, which may 

 not be visible even on careful inspection. If neither form of 

 injury is present the fungus is unable to make an entry. Certain 

 types of injury are not preventable, insect punctures and thorn 

 pricks for example, but experience in countries where this matter 

 has been closely followed up in the interests of important indus- 

 tries has shown that a very large part of the damage occurs in 

 the handling, and hence elaborate care is taken at every step of 

 the process which transfers the fruit from the tree to the distant 

 consumer. Such precautions as the wearing of gloves by pickers, 

 the use of padded collecting boxes, and the avoidance of falls 

 of even a few inches are at the opposite pole from local methods, 

 but they are adopted for strictly business reasons, and if ever a 

 successful fruit industry is to be established in these islands it 

 must first be realized that greater care is needed in the handling 

 of fruit for shipment than is necessary for handling eggs. 



In many fruits weak spots of another type are provided by 

 the cut end of the stalk, as in pineapples, or the socket from which 

 the stalk is pulled, while, if the end of the stalk is expanded by a 

 persistent calyx, to leave it attached provides cover under 

 which moisture collects and spores may germinate. In the first 

 type there may be advantage in leaving the stalk long or sealing 

 the freshly cut end, in the second dryness is the main protection, 

 and in some cases a touch of shellac varnish has been advocated. 



The best general protection is dryness, begun by packing 

 surface-dry fruit and continued by thorough ventilation. Even 

 injured fruit may carry if it is kept free from humidity. Packages 

 IIO 



