205 
The “ canker ” fungus of Hevea requires further careful investiga- 
tion; it is desirable that a large number of inoculations be performed 
with the fungus both on the pods and on the stem, for the purpose of 
establishing with some certainty its effect on the plant. Much remains 
to be done on the dispersal of the fungus and on its mode of entrance 
into the host, its capacity for living and reproducing itself on dead 
parts of the plant and its range of hosts in this country, in order that 
some accurate knowledge, may be obtained of such important factors 
as the facility with which the disease may be spread by a tapping- 
knife, the capacity of the fungus for passing from the fruits into 
the young branches with production of disease in them, in fact, in 
order that some accurate knowledge may be obtained of the methods 
of treatment which are likely to prove most serviceable in combat- 
ting the disease. 
In view of these considerations, it is proposed during the fruiting 
season to form an estimate of the amount of the disease in this country, 
and to carry out such inoculation experiments as will .lead to some 
knowledge of the life-history of the fungus and of the disease which 
has been attributed to it. 
Before concluding this note oil the “canker” disease of Hevea it 
is desirable to refer somewhat briefly to two fungi which occur on 
Hevea in this country, and which are regarded by some as being the 
cause of a disease to which the name “canker” is given. One of these 
fungi, Nectria diversispora, has been mentioned above ; the other is 
Stilbella Heveae. The fact that these two fungi are regarded by some 
as parasites on Hevea, coupled with the fact that they are frequently 
associated with effects on the tapping surface, which at first appear 
to be patholcgicaJ, has led me to make investigations on the two fung 
in order determine whether they existed merely as saprophytes or 
whether they were capable or causing any injury to the plant. 
Nectria diversispora was originally described by Petch on dead 
branches of Hevea and of Then viridis ; it was considered by him to be 
a saprophyte. Inoculation experiments described by him in the 
Tropical Agriculturist, Dec., 1909, served to show the harmless 
nature of the fungus. In this country the fungus occurs freely on 
dead twigs and branches of Hevea , on the dead parts of the trunk, and 
on the wood exposed by the splitting or breaking of the trunks. It 
takes the form of minute, red points which are sometimes aggregated 
in large numbers, each individual body being just visible to the naked 
eye. This is the mature form of the fungus, the Nectria stage. This 
stage is usually preceded by a white mould which is composed of two 
forms, a Spicaria-form, and a Fusarium- form. 
The ripe ascospores of the Nectria were found to germinate in a 
1% cane sugar solution in about 24 hours and to give rise to a mycelium 
which produced the Spicaria- form. In plate cultures, on agar-agar 
and a 10% extract of the juice of the sugar cane, the Spicaria- form 
appeared in five or six days and almost simultaneously the Fusarium- 
