44 
SPICES 
CHAP. 
and figured by Massee in the Keiv Bulletin (1892), 
p. 110, as Calospora Vanillae, Massee. 
This disease seems to have been noticed first in the 
Seychelles in 1887, when it was found that hundreds 
of pods were damping off, and it was observed that 
the finest and plumpest pods went first. They turned 
black at the end or in the middle, and in the course of 
a day or two fell off. 
The fungus which causes this is a minute species 
belonging to the group Peronosporeae, which attacks 
the leaves and stem of the plant. It appears as ex- 
tremely minute, dull red or amber coloured pustules 
springing in small groups from discoloured patches. 
These were found on both surfaces of the leaf, but 
for the most part on the upper side. This form of the 
fungus is known as the Hainsea form. Its mycelium 
spreading through the leaf destroys the tissue and 
causes the death of the plant by destroying the organs 
on which the plant depends for its food and for the 
regulation of its water supply. In such a case the 
youngest parts, farthest from the food supply, namely 
the young fruit and the aerial roots, show the first 
symptoms of disease, the fruit turning black and falling 
off, as described. 
When the leaf has become yellow and is dying from 
the attack of the fungus in this stage, a second form of 
the fungus appears in the form of yellow waxy masses, 
the Cytospora form, eventually presenting a blackened 
appearance, and finally a third form when the leaf is 
dead, the Calospora form. This form produces spores 
which enter the stomata of the leaves and develop into 
the mycelium of the Hainsea form. 
The Hainsea form in the diseased leaves cannot re- 
produce itself, but from its mycelium, when the leaf is 
dead, are produced the Calospora spores, which can 
attack healthy leaves and cause the death of the plant. 
It therefore follows that if all dead and dying leaves 
of the vanilla are rigorously destroyed by burning, 
the disease may be checked or exterminated. The 
