UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1286 
Washington, D. C. 
December 10, 1924 
SOUTH AMERICAN LEAF DISEASE OF PARA RUBBER 
By R. D. Rands, 1 Pathologist in Rubber Investigations, Crop Acclimatization 
and Adaptation Investigations, Bureau of Plant Industry 
CONTENTS 
Introduction 
History and geographic distribution 
of the disease 
Present status of the disease 
Trinidad 
British Guiana 
Dutch Guiana 
Description of the disease __ 
Life history and description of the 
causal fungus 
Perpetuation and spread of the dis- 
ease 
Page 
1 
UAH 
10 
11 
Environmental influences on the dis- 
ease 
Biologic factors 
Climatic factors 
Possibilities of control 
Control in "infected regions 
Exclusion from noninfect'ed re- 
gions by quarantine 
Summary 
Literature cited 
12 
12 
13 
13 
13 
15 
IS 
17 
INTRODUCTION 
The revival of interest in rubber cultivation in the American 
Tropics following a long period of indifference has stimulated a 
review of past attempts and a study of the factors which may deter- 
mine the success or failure of new enterprises. Unfortunately, the 
earlier efforts in tropical America were largely expended before the 
rubber-planting industry was established upon a scientific and prac- 
tical basis. Thus many ill-advised, quickly organized, and inflated 
enterprises sank millions of dollars in plantings of Castilla and 
other less suitable rubber trees, which could not compete with the 
rapidly expanding Hevea rubber culture of the Far East. The 
subsequent drop in rubber prices, the loss of confidence on the part 
of shareholders, and the relatively favorable returns from such 
crops as coffee, coconuts, and cacao led to a general abandonment 
of the rubber plantations. The industry gradually declined, so 
1 The writer wishes to express his thanks to Director W. G. Freeman, W. Nowell, F. W. 
Urich, and others, of the Trinidad Department of Agriculture ; to Sir J. B. Harrison, 
R. Ward, A. Abraham, and others, of the British Guiana Department of Science and 
Agriculture ; to Dr. Gerold Stahel and A. Reyne, of the Departement van Landbouw, Suri- 
name ; and to E. A. Robinson, owner of the Non-Pariel rubber plantation, Trinidad, for 
their most generous help and information and for plant-propagating material brought to 
the Panama Canal Zone. 
106650°— -24- 
