PENICILLIUM Sp. 



(Black Heart or Core Rot of Pineapple). 



Pineapples in Antigua were reported in 190 1 to be 

 suffering from this disease ; a similiar disease occurs in 

 Queensland, where the " Smooth Cayenne" variety is said 

 to be frequently attacked. 



A diseased fruit, as a rule, ripens unevenly, segments or 

 groups of segments here and there remaining pale-green in 

 colour ; if the fruit is cut open black patches can be seen 

 extending from the outside towards the centre, each patch 

 corresponding with a pale-green spot on the surface. 

 Later on, brown patches appear on the surface of the fruit 

 which becomes shrunken in places. 



A species of the genus Penicillium occurs in the 

 diseased fruitlets (" eyes "), and this fungus is thought to be 

 the cause of the disease. In Queensland inoculation 

 experiments have shown that the fungus can only effect an 

 entrance at a wounded surface, and punctures produced by 

 insects are considered to provide a point of entrance. In 

 the West Indies two insects commonly occur in the 

 diseased " eyes " ; the one is a mealy bug (Dactylopius 

 sp.) and the other a mite. It has been suggested that by 

 puncturing the rind these may afford a means of entrance 

 for the fungus. The disease, however, requires careful 

 investigation. 



Some species of Penicillium are known to be capable of 

 penetrating into fruits, and, to use the late Professor De 

 Bary's expression, " this they do the more easily, the 

 further the fruits are from the condition of full vital 

 energy." Penicillium italicum and Penicillium olivaceum 

 are the causes of " ripe rot" of the orange, citron, etc., 

 and Penicillium glaucum of the grape. 



STOCKDALE : West Ind. Bull., Vol. VIII., p. 161. 



MELIOLA Spp. 

 (Sooty Mould of Orange). 



The leaves, and sometimes the fruit also, of the orange 

 are frequently covered by a black incrustation which con- 

 stitutes the mycelium of a fungus belonging to the 

 Perisporiaceae. The mycelium forms a compact mem- 

 brane on the upper surface of the leaf, which frequently 

 cracks and peels off in patches. The fungus is not 

 parasitic, but merely follows aphides and other insects 



18 



