15 
In the following plots the vines were planted a year later, in 1915 (October) and ax-e con¬ 
sequently 2 years old. 
No. of plot. Treatment. Number of times Crop No 
treated. of pods. 
14 
Potassium phosphate, ammonium nitrate and coral 
8 
15 
„ " „ „ nitrate ... 
8 
• • • 
16 
,, „ and coral 
8 
• • • 
17 
Ammonium nitrate, Potassium Chloride and coral 
8 
• • t 
18 
,, „ guano and coral 
8 
19 
19 
Sea weed 
2 
20 
Fish manure 
2 
6 
21 
Coconut husk 
2 
8 
22 
Complete fei'tilizer ... 
3 
• • • 
23 
55 55 
3 
* . . 
24 
55 55 
3 
. . . 
25 
55 55 
3 
... 
One 
half of plots Nos. 14, 15, 16, 17 was treated by Bordeaux mixture 
in 
order to combat 
the disease but the vines which were treated 12 times in 1916 were treated only 3 times in 
1917 owing to shortage of copper sulphate which was only received from England in December 
1917 after 18 months unavoidable delay. In spite of the irregular treatment, the treatel vines 
were found to be in better condition than the untreated ones at the end of 1917. Only one 
treated vine had to be moved down and replanted owing to the dying out of the underground 
portion and of the aerial roots (a consequence of the disease) while in the untreated plot 4 
times more vines have had to be lowered in the same way. The quantity of copper sulphate 
available at the end of 1917 was only 20 lbs and this will not be sufficient to treat the plots 
more than a dozen times in 1918. In view of the fact that in the other plots the disease is also 
prevalent and in consequence the vines have to be replanted and even l’eplaced, the copper 
sulphate treatment should be adopted all over the ground occupied by vanilla at the Botanic 
Station. Hitherto the vines replaced are the following : one in plot 3, one in plot 5, one in plot 
19, two in plot 12, one in plot 13. If the disease continues to prevail the experiment will come 
to an end from lack of copper sulphate. 
In the following plots an experiment was made to see the effect of living grass on the 
growth of vanilla vines as compared with other vines of the same plant grown with a surface 
mulch of dry grass (Pennisetum or berbe ma tante). 
No. of plot. 
Treatment. 
Eesults. 
26 
27 
| plot covered with 2 inches of macadams % under com- 
melina grass (hei’be cochon). 
^ mulched with Pennisetum, ^ under Digittaria sangui- 
Diffei’ence in favour of 
macadams. 
In favour of grass. 
No diffei’ence. 
Grass better. 
55 
nalis (gros gazon). 
28 ^ mulched with Pennisetum, ^ under Panicum cvalifolium 
(gros chien dent). 
29 ^ mulched with Pennisetum, £ under Digittaria sp. 
(gazon). 
30 A mulched with Pennisetum, ^ under Axonopus com- 
pressus (chien dent bourrique). 
31 \ mulched with Pennisetum, ^ under Oplismenus com- 
pqsitus (chien dent). 
32 \ mulched with Pennisetum, ^ under Paspalum mandio- 
canurn (herbe Perard). 
33 This plot was set out with Bevilaqua (Hydrocotyle 
asiatica). 
34 ^ mulched with Pennisetum, | under Digittaria sp. 
(grande her be Perard). 
35 \ mulched with Pennisetum, \ under Panicum parvi- 
folium (herbe Edwards). 
These plots are only one year old. They are set out in poor laterite soil and the beds are 
jiot forked but simply walled in by a layer of stones. The gi’ass seems to keep the foot of the 
vanilla plants in better condition as far as the experiment goes. The use of macadams instead 
of mulch produced excellent results. The macadam in question is simply broken pieces of 
granite about the size of a pigeon egg placed on the surface of the bed in a layer of 2 inches 
Five beds with vanilla 1 year old are also used as follows 
No. of plot. Treatment. Eesults. 
No difference. 
The grass was destroyed 
by snails. 
Grass better. 
„ much better. 
19 
Sea weed allowed to dry a little before application 
No flowei’. 
20 
Fish manure 
6 pods. 
21 
Coconut husk 
6 „ 
36 
Coral sand 
No flower. 
37 
Horse manure 
55 
Coconut and fish manure seem to be very beneficial. In plot 19 manui-ed with sea weed 
more rootlets from the shade ti-ees are fouud hampering the growth of vanilla. Few rootlets 
from the shade trees develop in the beds manured with coral sand. Horse manure seems 
Jreneficial; there is no killing out of the vines at all as anticipated by many persons. 
