65 
of inducing infection with the actual presence of the fungus in 
dieback tissues and its proved powers of penetrating coffee-wood 
blocks, until one takes up the mycological investigation of the 
insect pests of coffee. Of these one of the most dangerous is 
the Variegated Bug (Antestia orbitalis, Westw. var. faceta. Germ.) 
which punctures and sucks the juices from. twigs, buds, and 
berries. In the study of the broken and chipped beans which 
on curing are frequently found inside what appear to be perfectly 
sound-skinned cherries, it occurred to the writer that the fungus 
found on such “lights” might possibly be introduced by the 
Variegated Bug. 
This theory was put forward in 1916* when the appearance 
of the Bug in dangerous numbers coincided in time with the 
occurrence of the broken beans. Then, as now, pycnidia of the 
same species of Phoma as is found on the branches were invariably 
found on small “cankers” on the cotyledons. In order to 
throw light on this supposition, legs and beaks of the Variegated 
Bug were taken.from the insects with sterile forceps, shaken up in 
prune-agar and sugar-cane agar, and poured into plates. In all 
the cultures, except one which was productive of bacteria and 
moulds only, Phoma mycelium appeared aerially in forty-eight 
hours. None of the cultures was pure in the sense that it con- 
tained a growth of one species of fungus or bacterium only, for 
the Fusarium sp. was found in sixty per cent., moulds in eighty, 
and bacteria in twenty per cent. If, as appears probable from 
these facts, the Bug carries the spores of Phoma in or on its beak, 
that is, in or on the organ it introduces into tender tissues in 
order to suck, it is to be concluded that this pest is to blame 
not only for the broken beans but also for the presence of Phoma 
- in tissues which it may be incapable of penetrating without the 
help of an outside agent. 
It is somewhat remarkable that Colletotrichum was altogether 
absent from these Variated Bug beak and leg cultures, but this 
may have been due to the circumstances of the moment. Again, 
no other pest from among the seventeen scale insects known on 
Uganda coffee, or the aphids, or other plant bugs (Lycidocorus 
mimeticus, R. and P., and Piezodorus pallescens, Germ.) or borers, 
etc., has been examined on these lines, and there may be no 
reason why all or any one of these should not carry and introduce 
into attacked tissues both Colletotrichum and Phoma. The 
former alone has developed on obviously: bug-smitten branches, 
but it may have been present as a saprophyte, for numerous 
acervuli of Colletotrichum will develop on previously healthy 
fresh branches when plucked and kept in the damp. Similarly, 
Phoma pycnidia can be found on healthy branches, apparently 
causing no harm and probably lying in wait, as it were, 
initiate a vigorous attack on the weakening of the tree owing to 
the results of unfavourable conditions such as_leaf-disease, 
* Small: Notes on a few Ug. diseases of plants, Ug. Pl. Assn. Yr. Bk. 
1916-17, p. 135. 
