4 COFFEE BUG AND COFFEE MILDEW. 



pearance of the tree is scarcely altered : the following year, how- 

 ever, brings a change for the worse with it. The scales are 

 found to have become more numerous, and if the young shoots 

 and the under side of the leaves are examined, they will be 

 found to be covered with numberless white specks, which prove 

 to be the young scales in a more or less forward state. The clus- 

 ters of berries liave assumed a black, smutty appearance ; have a 

 more numerous crop of scales than during the previous year; 

 and, if tlie clusters are watched, it will be found that a number of 

 their berries fall ott' before coming to maturity. The general health 

 of the tree now also begins to fail, and it acquires a blighted ap- 

 pearance : a loss of crop is sustained, but not to any extent. 



" The third year brings about a still greater change. The 

 whole plant has then assumed a deep black colour, having all 

 the appearance of soot having been thrown over it in great 

 quantities. This colour is caused by the growth of a black pa- 

 rasitic fungus on the young shoots, and the upper surfaces of the 

 leaves, where it forms a thin fibrous coating, not unlike a piece 

 of velvet or felt. When this substance is examined with a pow- 

 erful microscope, it is found to consist of a dense interlaced 

 mesh of fibres, each made up of a single series of minute oblong 

 vesicles applied end to end. It never makes its appearance on 

 the tree till after the coccus or ' bug ' has been a long time on 

 it, and is no doubt produced by the unhealthy state to which the 

 plant has been reduced, owing to the vitiation of its juices by tiie 

 insect. As certainly as tlie scale never ap|)ears on the upper 

 surface of the leaf, so surely does the fungus never appear on 

 the under one. 



" At this period the young shoots have an exceedingly dis- 

 gusting look, from the dense mass of yellowish pustule-like 

 scales that are forming on them. The leaves, in consequence of 

 the abstraction of their juices alike by the animal and the vege- 

 table parasite, become shrivelled and evidently diminished in 

 size ; and the trees, which, in their healthy state, appeared to 

 cover the ground, now seem to stand out singly. On the best 

 trees thus infested, more than two-thirds of the crop are lost, 

 and, on many, scarcely a berry is to be seen. 



*' Besides the ' scale,' there is another species of coccus some- 

 times found on coffee-trees, but never t,o the same extent as the 

 other. The female of this ivind never changes into a scale, but 

 wraps herself up in a white cottony matter after impregnation, 

 and there producing her eggs, dies. It has sometimes been ob- 

 served on coffee estates previous to the appearance of the scale, 

 but tliere is evidently no connexion between them. 



" So far as 1 have been able to ascertain, the coffee trees of 

 the island were never affected vvitli the ' scale ' till the year 



