6 BULLETIN 1286, IT. S. DEPARTMENT OF AGRICULTURE 
corroborated with respect to the Federated Malay States by Bel- 
grave (4), who published a report on the leaf disease following a 
short visit to Trinidad and British Guiana in 1921. In his recent 
treatise on the diseases of rubber Petch (17, p. 78-81) likewise affirms 
that this leaf disease is confined to the American Tropics. 
PRESENT STATUS OF THE DISEASE 
TRINIDAD 
Although Borer (19) found the South American leaf disease wide- 
spread throughout the island of Trinidad in 1916, it has not been 
solely responsible for the lack of expansion of the rubber plantation 
industry there. A brief survey of agricultural development of the 
island during the last two decades shows that interest in rubber prob- 
ably began to wane not only before the leaf disease was known but 
even before much Hevea was planted. In a comprehensive report on 
rubber cultivation in Trinidad and Tobago by a special committee of 
the local Board of Agriculture in 1917 (14) , it was shown that some 
rubber had been planted on at least 155 estates, of which most had 
unfortunately used Castilla, Hevea having been planted "except in 
a very few instances, only upon an experimental scale, or among 
cacao or along the edges of cacao fields." This mistake in the use of 
the wrong species of rubber plant seems not to have been fully real- 
ized until the period of high prices had practically passed ; but, com- 
bined with the inducements offered in cacao, sugar cane, and coco- 
nuts, it gave rubber planting a setback from which it has apparently 
never recovered. 
When the writer visited the island of Trinidad he found that most 
of the Castilla and Funtumia (also considered undesirable) had 
been cut out and that many of the scattered Hevea plantings were 
in a derelict condition. In some of these, especially in the southern 
districts, leaf disease was rampant at the time, as shown by the slow 
growth, die-back, and ragged, shot-hole appearance of leaves. (PL 
II, fig. 1.) Even here, scattered trees along the roadside in more 
exposed sites showed nearly normal development. In the northern 
district the small government gardens on River Estate and at the 
St. Clair and St. Augustine experiment stations near Port of Spain 
seemed to have suffered but little, although young seedlings spring- 
ing up beneath the same trees and in near-by nursery beds were 
often badly infected. Likewise, on the eastern coast, where the 
only plantings of considerable extent occur and are now being 
tapped, the disease has been of small consequence. The Non-Pariel 
and Rydal Hall estates, on which nearly 50,000 trees, mostly in 
pure stands, occur, give one much the same impression as any well- 
kept Far Eastern plantation. (PL I.) Although rather closely 
spaced, the trees as a rule are well developed, and the yields of first- 
quality smoked sheet are said not to be under those of similar estates 
in the Orient. Even here numerous young seedlings in the drain- 
age ditches and along the edges of the fields were generally infected 
with the leaf disease. On the 10 to 16 year old mother trees, how- 
ever, no evidence of repeated earlier defoliations and the consequent 
die-back or of leaf attack at the time was observed. The probable 
reason for this fortunate state of affairs is found in a climatic dif- 
ference discussed fully under a later heading. 
