PART 1V.
CHAPTER IV.
COCONTUTS.
GUMMOSIS IN COCONUTS.
Miss WELSFORD read the following paper: —
During the last ten years an Increasing amount of attention has
been given to a disease of coconuts which is spoken of as excessive
nut fall and which is the cause of a diminished crop. It has been
attributed to various causes.
The disease was reported from Indo-China in 1920 where it was
attributed to lack of nitrogen; in 1921 Gadd recorded it in Ceylon and
showed that in that country it was not due to lack of nitrogen but
attributed it to a Phytopthora; three years later he showed that it
was not due to a fungus but was caused by mechanical injury; in 1924
Sandararaman in Malabar attributed it to Phytopthora, and in the
same year Simmonds in Melanesia found it associated with
Botryodiplodia theobromae. In Kenya, McDonald found it was due
to insufficient moisture and unfavourable soil conditions. It has also
been reported from Tanganyika.
In Zanzibar and Pemba the disease is widespread: not one
shamba in the Protectorate is known to be entirely free from the
disease; it has been very noticeable every year since 1921 when I first
came to Zanzibar and has increased during the last two years.
SYMPTOMS.
The chief symptoms of the disease in Zanzibar are :
I. A great reduction of the crop at all seasons of the year due to
(a) Abortion of flowers.
(b) Dropping of developing nuts at all stages.
(¢) Non-development of inflorescences.
* Associated with this nutfall a deformity of nuts caused by
(a) Twisted and irregular growth of nuts.
(b) Formation of lesions in husk.
(¢) The production of drops or masses of hardened gum on
the husks.
So far as I know this splitting of husks and gummosis has only
been recorded from East Africa. I should like to know if it occurs
elsewhere. Not only is the disease in Zanzibar serious in that it
enormously reduces the crop but also because the nuts which are
produced, are to a great extent of very poor quality yielding a small
amount of meat and very inferior fibre.

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