9 
attempt having been made to introduce other new plants from Mexico, or to create more 
disease resistant varieties, by means of cross pollination and selection. It is well know? that 
varieties of plants reproduced only from cuttings have a greater tendency to degenerate ad to 
become tbe prey to diseases, than strains obtained by selection from seedlings. lu rht ay 
the creation of new varieties goes far to check the degeneration of old strains and allows the 
planter to replace the latter, when it is diseased beyond recovery. 
The infiuen.ee of the four factors, which may explain the shortage of crops, is being felt 
severely all over the Colony and at present the practice is to plant vanilla in localities where 
tbe orchid has not as yet been grown as extensively as in Mahe. In this Island the disearse is 
so bad that very promising plantations have been wiped out by it just after a very good flo wer¬ 
ing. Planters who have witnessed such calamities will undoubtedly withdrew gradually from 
vanilla planting. 
A series of plots has been arranged this year (1916) in order to determine the influence 
of Bordeaux mixture in checking vanilla disease due to “Calespora vanillae”. A series of 
vanilla beds were divided into two parts : one part was sprayed with Bordeaux mixture, once 
a week for 12 weeks, up to the end of 1916 ; and the other part was left as control. Neutral 
Bordeaux mixture was used. After 12 weeks not a single leaf of vanilla showed signs of having 
bee)i scorched and the plants continued to make excellent growth. The behaviour ol the vines 
■will be followed until the next flowering season, when they are expected to come into bearing, 
and the necessary deductions ■will be drawn. The fungus is saprophytic and lives in dead 
leaves as well. The mulch on the ground is also sprayed and 4 litres-of Bordeaux mixture are 
used per vine, each time. 
MANURING EXPERIMENTS. 
Part of the experimental plots Nos 1 to 13 had been in hand 2 years on the 20tb July 
1916, and the following results are recorded, vanilla having flowered and fruited this yeir ou 
several plots:— 
of plot. 
Treatment. 
No. of times 
treated. 
No. of pods obtained 
during the year. 
Observations. 
1 
No manure. 
2 
Leguminous mulch. 
io 
5 
only 1 vine flowered 
out of 7. 
3 
Ordinary mulch. 
19 
. . . 
. • . 
4 
Lime. 
4 
k • . 
5 
Phosphate. 
4 
• . . 
. . . 
6 
Complete fertilizer. 
4 
• . . 
. . 
7 
Complete soluble fertilizer. 38 
39 
4 
vines flowered out 
of 7. 
8 
Potassium sulphate. 
38 
39 
3 
9 
„ chloride. 
38 
16 
2 
99 99 
10 
Ammonium nitrate. 
38 
• • • 
11 
Sodium nitrate. 
38 
22 
1 
99 9P 
12 
Complete fertilizer. 
4 
32 
2 
99 9? 
13 
No manure. 
. . . 
19 
2 
99 99 
It is premature to make deductions from the above experiments, the vines being a little 
over 2 years old. Vines generally come into bearing when they are 3 years old, at least. It 
may however he stated that the two best yields were obtained from complete fertilizers. These 
fertilizers are obtained from the firm TrufPaut & Co., Versailles, and they are cheap and of 
uniform composition. 
The principal difficulty experienced in these experimental plots is the presence of huge 
shade trees : Parkia and Alhizzia which throw out into the vanilla beds numerous rootlets 
■which check the plants. These rootlets have to be dug out continually and show clearly to 
what extent vanilla is injured by huge trees growing near by. There is no doubt that this 
factor will have to be taken into account in deducing conclusions from these experimental plots 
■which should, as already recommended, have been set out on the hills, without shade trees. 
Tanilla does not grow without shade in the low country. Another difficulty is the diseased 
condition of a few vines which have to be treated with Bordeaux mixtures, as the experiment 
would he upset if one of two vines were killed out. 
The vanilla vines growing under Gliricidia shade have done hitherto well; the plants not 
being checked by rootlets as in the case of Parkia and Albizzia. The vines of this plot are 
manured only with the green dressings obtained by lopping the branches of Gliricidia about 
4 or 5 times a year. The manure in this case is provided by the prop itself. This plot has 
been arranged because it is the custom in this Colony to manure vanilla in that way onlj's 
save that the props generally used are not leguminous plants like Gliricidia which absorbs 
nitrogen from the air and improves the soil in which it grows. 
CHAPTER VIII. 
THE RUBBER INDUSTRY. 
The production of rubber during 1916 amounted to 2739 kgs., valued at Rs 6746, or ten 
times more than last year. The tapping of rubber began spasmodically in 1911. There is 
fitill a very small number of trees tapped (4000) although during the yeai’, much more atten- 
