S. SUNDARARAMAN 2h 
infection—infection from plant to plant favoured by conditions of moisture 
and atmosphere, that is, rainy weather followed by wind and moist muggy 
weather. The disease appears in August and seems epidemic in years of 
heavy rainfall. Continued rain with spells of dry weather is congenial for 1ts 
development. The rains wash down the fungus spores to lower portions of 
the plant, and the wind carries the spores from leaf to leaf and from plant to 
plant. The cultivator produces conditions favourable to the disease by his 
thick planting which tends to make plants touch each other, not admitting 
light and air which are essential for healthy vigorous growth. 
Effects of the disease. 
The disease appears on the leaves. This is the part where the plants 
manufacture food. The disease makes its appearance in the growing period of 
the crop and at a time when the rhizomes begin to develop. As the fungus 
attacks directly the place where plant food is manufactured, the plants get 
stunted and the rhizomes do not develop. Under healthy conditions the 
crop stands in the ground from July to March but when the disease comes on, 
the crop has often to be lifted early before the plants begin to die. 
Description of the fungus. 
The sporodochia appear in pale yellow spots varyingin size. They are 
aggregated together in dense clusters, circular to oval in outline, black in 
colour, 50-140 » in diameter (Plate I, fig. 1) ; setee numerous, erect, dark brown, 
septate, 85-168 » long (Plate II, figs. 2 & 3) ; spores, subfusoid, curved with a 
blunt point, hyaline, minutely guttulate, 17°5-24 » x 3°15-4:°2 » (Plate II, 
fig. 4). On leaves, petioles and scale-like leaves on the rhizomes of ginger in 
Amalapur Taluk, Godavari District. 
The hyphe are hyaline and septate. They vary in diameter from 2 to 8p. 
In old culture the hyphz become light brown. ‘The spore clusters are formed 
partially submerged under the epidermis but on breaking the epidermis come 
out to the surface, and take on the character of Colletotrichum, the sete appear- 
ing to spring from the layer of sporophore (Plate II, fig. 3). The spores 
germinate in 4-6 hours, putting forth a germ-tube, and produce chlamydospores 
in 18 hours. These are formed at the end of germ-tubes (Plate I, fig. 5, a, 
b, c, d). Some spores form chlamydospores without the intervention of the 
germ-tube. The chlamydospores are sometimes divided into cells each having 
a germ-pore. These are either round or ovate or irregularly lobed and are 
generally dark-olive. When the spores begin to germinate they produce a 
