DISEASES OF MINOR FRUIT PLANTS 351 



green or ripe, and is responsible for the largest part of the losses 

 which take place in storing and shipping pines. Its incidence in 

 the field, where it occurs on ripe fruits, is inconsiderable as a rule. 

 While infection usually takes place through wounds, experiments 

 have demonstrated that in a moist atmosphere the germinating 

 spores can penetrate the surface of uninjured fruit. 



DiPLODiA Core-Rot. 



In the traffic between these islands, pineapples which have 

 been some days in transit are frequently found to be infected 

 through the cut end of the stalk by a species of Diplodia. The 

 fungus passes up the vascular core of the fruit, from which it 

 spreads to the adjoining pulp. It produces a water-soaked 

 appearance of the tissues recently invaded, and these are later 

 darkened by the development of brown coloration in the 

 mature mycelium infesting them. The fructifications of the 

 fungus appear as dots under the rind of the fruit near the stalk, 

 later breaking through as pustules and discharging immature 

 white or mature black spores which in the latter condition are 

 two-celled. 



Diplodia wound infections of ripe or ripening fruits are very 

 common in the West Indies (see p. 25), and the one or more 

 species causing them are quite generally distributed. 



Prevention of Fruit Rots. 



The measures to be adopted for the prevention of these 

 troubles are largely matters of handhng and packing arising 

 principally in connection with export ; though it must be remem- 

 bered that the intrusive fungi develop so rapidly in a tropical 

 climate that fruit intended for local consumption is liable to be 

 quickly spoiled. 



In dealing with the fruit it should be taken for granted — it is 

 indeed usually a fact — that spores are present and only await 

 suitable conditions for their development. These conditions 

 are supplied by the presence of moisture and a certain degree of 

 heat. Unless the fruit is artificially cooled the latter may be 

 taken as in all cases sufficient, and it is on the control of the 

 former that success will depend. The requisite moisture may be 

 supplied by the juices of the fruit on cut or bruised surfaces, or 

 by the water given off by the fruit accumulating either on the 

 packing material or in surrounding air enclosed or allowed to 

 remain still. 



It follows that the pineapples must throughout be handled 

 with the greatest care to avoid bruising or scratching. They must 

 not be broken off from the stem, but cut with a stalk 3 or 4 

 inches long, which itself must not be stripped. It would probably 



