58 
out in 1915,* other. fungi were found on dieback branches, viz., 
Periconia byssoides, Pers., Phoma sp., Fusarium  coffeicola, 
Henn., a second species of Fusarium, and Tubercularia sp. 
It was also emphasised that various physiological factors were 
involved in the production of dieback. The Phoma and Tuber- 
cularia were at that time scarcer than the other fungi, and none 
of the forms was constant in its presence on dieback branches. 
Moreover, the mode of parasitism seemed unusual. The Pert- 
conia and Tubercularia were always regarded as saprophytes, 
and recent worky has shown that both the species of Fusarium 
should be placed in the same category. Other forms found at 
times on dieback coffee branches are the perithecia of Capnodium 
brasiliensis, Putt., the fungus of sooty mould, and of a species of 
Glomerella, the complete stage of Colletotrichum coffeanum, which 
is found after the lapse of three or more months on twigs kept 
in the damp, an ascomycete which may be the ascigerous stage 
of the Phoma, and a Coniothecitum which forms a stage in the 
life-history of the Phoma. The supposed ascigerous stage of the* 
mais very rare. At the present day, the preponderance of 
numbers is at times in favour of Colletotrichum, at others in 
favour of Phoma 
Histological examination of certain dieback coffee branches 
discloses the presence of mycelium ‘in the tissues of wood and 
cortex. This mycelium is septate, branched. and pale brown or 
hyaline in colour, and it may be nodulose. It penetrates trans- 
verse cell-walls, disorganises longitudina! cell-walls, and so works 
its way between adjacent cells as to bring about splitting and 
cracking. It impregnates the cortical tissues more fully than 
those of the wood, and it consumes the cell-contents, for none 
are visible where invading hyphae are present. This mycelium 
can be shown to belong to Phoma or Colletotrichum ; the nodulose 
mycelium would appear to be that of 
In the elucidation of the parts played by the different fungi 
associated with coffee dieback in. Uganda, it was found necessary 
to grow in pure culture Colletotrichum, Phoma, Fusarium coffei- 
cola and Fusarium sp., these fungi being more consistent in their 
presence on dieback branches and seeming to be more implicat 
prune, coffee-leaf, or cacao-pod extract or decoction. The fungi 
were also grown on sterilised coffee-wood blocks and coffee 
leaves. Inoculations of the various media were made by the 
direct transfer of spores on the pcint of a sterile needle, or by 
suspending the spores in a drop of sterile distilled water and 
bee a platinum loop. 
lietotrichum coffeanum in pure culture.—Conidia of Colleto- 
trichum germinate readily at laboratory temperature in a few 
* Annual Report, re be Agric. Uganda, 1914-15, p. 61. 
+ Small: Dieback of Coffea arabica in Uganda: Cire. No. 4, Dept. 
Agric. 1920. 
