RUBBER (HEVEA) DISEASES 49 
The great variability in the spore forms found in different col- 
lections, together with the absence in most cases of the ascigerous 
stage, has made it impossible in some cases to refer definitely the 
organisms. The forms most commonly observed have been referred 
to Copnodhun brasiliense and 0. lanomm. 
A species of Meliola forming thin sooty spots on the young leaves 
of Hevea is of common occurrence in very wet situations. The 
material was immature and did not conform to the description for 
M. heveae. Hennings also reported a species of Meliola which he 
considered related to M. amphitrieha. 
The injury resulting from the growth of sooty molds is of slight 
degree, but if the incrusting hyphse remain on the leaf for 
protracted periods, thereby shutting off the light from the chlo- 
rophyllaceous cells of the leaf, some damage may result. The 
leaves lose their green color and eventually fall. In damp shady 
situations during periods of little rainfall trees under heavy canopy 
may be defoliated, causing an infection of twigs by secondary fungi. 
The growth of the fungus is closely associated with the honeydew 
of insects; hence the obvious method of control is to destroy the in- 
sects by spraying with kerosene emulsion. The fungus is common 
on jungle trees and bushes. It would be good practice to remove 
heavy jungle growth from the near vicinity of rubber trees. 
ENTOMOGENOUS FUNGI 
In contrast to the sooty molds there are several parasitic fungi 
which prey upon insects secreting honeydew. They may be con- 
sidered beneficial by destroying insects which otherwise may cause 
injury to the leaves. 
One of the most common species of this group sometimes found 
on young and old leaves of Hevea is Hypocrella reineckiana. This 
fungus usually in its lower or Aschersonia stage develops over the 
body of a single insect, forming boat-shaped or spherical nodules. 
They are attached to the upper side of the leaf by a flattened base 
and may be easily removed. These nodules are usually strikingly 
colored with shades of yellow, brown, or orange when young, but 
become black when old. Internally they are yellow or orange 
colored. The fungus is entirely parasitic on the scale insect and 
does not affect the leaf. 
Several different species of scale insects were found on leaves 
of Hevea, and they were in most cases parasitized by fungi. The 
fungTis either envelops the entire insect, as in the case of the above- 
named species, or grows out around it, forming a white fringe. 
Cephalosporium lecanii, Aschersonia, Aleyrodes, and Hypocrella 
verruculosa were also found on scale insects on Hevea. 
EPIPHYTIC AND PARASITIC ALGiE ON LEAVES 
On the smooth, hard, polished upper surface of leaves and on 
stems of many species of jungle trees are found reddish, greenish, 
or whitish flattened scurf like thalloid patches. These patches are 
the fructifications of epiphytic and parasitic algae. The surface of 
61384°— 26 4 
