CITEUS DISEASES. 103 



addition to the forms of disease already described, produces a soft 

 rot of the fruit to a limited extent. Typical anthraenose spots first 

 appear, and under favorable conditions the rot spreads so as to in- 

 volve the entire fruit. In a majority of cases, however, anthrac- 

 nosed fruit is rotted by Diplodia or blue mold, which gain entrance 

 through the anthraenose lesions. Held under ordinary room con- 

 ditions, a very large percentage of the anthraenose spots fail to con- 

 tipue their development, and an infected fruit ultimately dries up, 

 unless attacked by one of the other fungi. 



As already noted, the fungus involved in this t_ype of decay is 

 only weakly parasitic, and uninjured fruit from liealthy trees will 

 be practically free of it. To prevent loss from this source the meas- 

 ' ures outlined a))ov(^ for blue mold will be applicable. 



Several fungi of decidedly minor importance have been noted 

 on rotting fruit, for the most part merely secondary {Aspergdllwi 

 spp., Rhizopus sp.), though occasionally as ])rimary agents, but al- 

 ways entering through wounds. Control will be the same as for 

 blue mold. 



BLOSSOM END ROT. 



Two types of blossom end rot have been distinguished in Porto 

 Rico, which for convenience have been designated as the pink and 

 the black. Both have similar external symptoms, the course of 

 the infection and rotting is the same, and control measures are iden- 

 tical. Apparently only oranges are subject to attack, the navel 

 orange to some extent, but other varieties more in particular. The 

 disease is more prevalent, or at least causes most visible damage, 

 at the beginning of the shipping season, infected fruit becoming 

 less and less as the season advances and seldom being found after 

 November. The disease is more prevalent in some years than in 

 others, apparently dependent upon certain climatic influences. 



The only marked external symptom is the bright orange color 

 of infected fruit in marked contrast to the yellow or yellow-green 

 of the normal fruit. Porto Rican oranges, at least those from cul- 

 tivated groves, seldom become so highly colored. Following the high 

 coloring, and sometimes to be seen liefore the fruit drops, there 

 appears a brown, sometimes slightly sunken area at the blossom 

 end, from four to ten millimeters in diameter. 



On cutting into the fruit there is most commonly found a brown 

 rot along the rag, which ultimately involves the sections as well. 

 In the early stages there appears merely a discoloration in the skin 



