AGRICULTURAL BULLETIN 
THE 
STRAITS 
•AND 
FEDERATED MALAY STATES. 
No. 7 .] JULY 1911. [Vol. X 
A NOTE ON THE CANKER OF HEVEA 
BRASILIENSIS. 
By Keith Bancroft, B.A. 
Assistant Mycologist, Department of Agriculture, F.M.S. 
The “canker” of Para rubber was first investigated by Carruthers 
in Ceylon in 1903-04. Like the “canker” of cacao it owes its name 
rather to the fungus (Nectria spj to which it was first attributed, than 
to the effects produced by the disease. On Hevea plantations in 
Ceylon there has not been much damage caused by “canker”, but in 
mixed cacao and Hevea cultivations the disease is regarded as being 
more serious. Hitherto there has been no record of its occurrence in 
this country. 
The symptoms are the following: — 
External symptoms at first are obscure; on young trees the bark 
may appear to be a little darker in colour, but on older trees there 
are no observable external symptoms at the commencement. The 
first symptom which is usually recorded is the cessation of the flow 
of latex ; when this occurs, if the outer bark be scraped away, a black 
■layer is found under which the latex layer is obviously discoloured 
When recently diseased the inner tissues possess a grey or neutral 
tint with a well-defined black border, but in advanced cases of disease 
they become of a claret or purple colour. In some cases a purplish 
red liquid is exuded from the diseased parts. These are briefly the 
symptoms described by Petelf in. the Circulars and Agricultural 
Journal, Royal Botanic Gardens, Ceylon, Vol. V, No. 13, 3910. 
