WORLD BANK TECHNICAL PAPER NUMBER 39 WTP39 May 1985 Cocoa Production Public Disclosure Authorized Present Constraints and Priorities for Research 3ECTrORAI LIBRAR'Y INVTERNATIO.NALHANK R. A. Lass and G. A. R. Wood, editors REcONSTucloN DEVELOPMENT JUL9 1985 Public Disclosure Authorized Public Disclosure Authorized 267 X.59 1985 FILECOpy ,1 Public Disclosure Authorized WORLD BANK TECHNICALPAPERS No. 1. IncreasingAgricultural Productivity No. 2. A Model for the Developmentof a Self-helpWater Supply Program No. 3. Ventilated ImprovedPit Latrines: Recent Developmentsin Zimbabwe No. 4. The African Typanosomiases: Methods and Concepts of Control and Eradicationin Relation to Development (No. 5.) StructuralChanges in World Industry: A QuantitativeAnalysis of Recent Developments No. 6. LaboratoryEvaluation of Hand-operatedWater Pumps for Use in DevelopingCountries No. 7. Notes on the Design and Operation of Waste StabilizationPonds in Warm Climates of Developing Countries No. 8. 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Water Quality in HydroelectricProjects: Considerationsfor Planning in Tropical Forest Regions ( ) Indicatesnumber assigned after publication. (List continues on the inside back cover) WORLD BANK TECHNICALPAPER NUMBER 39 Cocoa Production Present Constraints and Priorities for Research R. A. Lass and G. A. R. Wood, editors The World Bank Washington, D.C., U.S.A. Copyright (© 1985 The International Bank for Reconstruction and Development/THE WORLDBANK 1818 H Street, N.W. Washington, D.C. 20433, U.S.A. All rights reserved Manufactured in the United States of America First printing May 1985 This is a document published informally by the World Bank. In order that the information contained in it can be presented with the least possible delay, the typescript has not been prepared in accordance with the procedures appropriate to formal printed texts, and the World Bank accepts no responsibility for errors. The publication is supplied at a token charge to defray part of the cost of manufacture and distribution. The World Bank does not accept responsibility for the views expressed herein, which are those of the author(s) and should not be attributed to the World Bank or to its affiliated organizations. The findings, interpretations, and conclusions are the results of research supported by the Bank; they do not necessarily represent official policy of the Bank. The designations employed, the presentation of material, and any maps used in this document are solely for the convenience of the reader and do not imply the expression of any opinion whatsoever on the part of the World Bank or its affiliates concerning the legal status of any country, territory, city, area, or of its authorities, or concerning the delimitation of its boundaries or national affiliation. The most recent World Bank publications are described in the annual spring and fall lists; the continuing research program is described in the annual Abstracts of Current Studies.The latest edition of each is available free of charge from the Publications Sales Unit, Department T, The World Bank, 1818 H Street, N.W., Washington, D.C. 20433, U.S.A., or from the European Office of the Bank, 66 avenue d'Ina, 75116 Paris, France. R. A. Lass in an agricultural manager for, and G. A. R. Wood was, until his retirement, an advisor on, cocoa production and research for Cadbury Schweppes Limited. Library of Congress Cataloging in Publication Data Main entry under title: Cocoa production. (World Bank technicalpaper, ISSt 0253-7494 ; no. 39) 1. Cacao. 2. Cacao--Research. 3. Cocoa. 4. Cocoa-- Research. I. Lass, R. A., 1943- . II. Wood, G. A R. (GeorgeAlan Roskruge), 1920- . III. Internationai Bank for Reconstructionand Development. IV. Series. SB267.C59 1985 633.7'4 85-9290 ISBN 0-8213-0512-3 - iii - ABSTRACT Cocoa is produced almost exclusivelyby developingnations in the tropics. Although it is in many ways a suitable crop for small farmers, yields are seriously reduced by several major pests and diseases. This paper identifiesthe major constraints,summarizes the present state of knowledge,and suggests priorities for research that would be expected to have the greatest impact at the farm level. Financialconstraints and thus lack of continuity in research have hindered progress. The botany, historicaldevelopment, social aspects, and environmentalrequirements of cocoa are covered. The agronomy section deals with rehabilitatingold cocoa, the role of cocoa in farming systems, and the general husbandry of the crop. This is followed by discussion of cocoa physiology,and the relation of shade and nutritionalrequirements. There are both economic and social constraintsto the adoption of more sophisticatedfarming systems by small farmers. Much effort has been devoted to developingresistance to pests and diseases. The relative merits of Amelonado and the more recent hybrid varieties are discussed,and the genetic resource base is summarized. Priority should be given to further genetic prospection,broadening the range of genotypes in the current programs,as well as to establishingnew collections. Conventionalmethods of vegetativepropagation need more work on stock-scionrelations, while micro-propagationtechniques should be developed. Black pod disease (Phytophthoraspp.), is estimated to destroy 10 percent of the world crop annually. Research is required to improve current chemical and phytosanitarycontrol measures. While breeding for resistanceis the ideal long-term solution, there are many difficulties. The report also covers witches' broom, frosty pod rot, and vascular streak dieback. Of the viruses, swollen shoot disease receives the greatest attention. Pest managementin cocoa is generally inadequate. For mirid control priority should be given to testing new insecticidesand studying the present status of resistanceto gamma-HCH. The possibilityof biological control should be re-explored. For the other pests, the programs need to be intensified. Primary processing is described and the shortcomingsof the present methods are identified. Quality at the farm level could in many instancesby improved by greater attention to the incentive system. Also proposed are closer contacts between producersand the major buyers to promote a better understandingof market requirements. I v TABLE OF CONTENTS PREFACE xi I. INTRODUCTION 1 II. THE COCOA TREE AND ITS CULTIVATION (G.A.R. Wood) 3 2.1 Botany 3 2.2 Historical Development 4 2.3 Social Aspects 6 2.4 Environmental Requirements 6 Climate 6 Soils 6 2.5 Cultivation 7 2.6 Processing 8 III. AGRONOMY AND PHYSIOLOGY 9 3.1 Perspectives 9 The Problem of Declining Yields with Time 9 The Problem of Rehabilitating Old Cocoa 9 Cocoa Production and the Farming System 9 3.2 Cocoa Agronomy (R.W. Smith) 10 3.3 Cocoa Physiology (W. Hadfield) 13 Seed 13 Seedlings 13 Planting Out 15 Shade 15 Mature Cocoa 16 Disease and Decline 17 3.4 Shade and Nutrition (M. Wessel) 18 Shade Requirements 18 The Interrelationship between light Intensity 19 and Nutrition Nutrient Requirements 20 Leaf Analysis 21 Fertilizer Recommendations 22 Needs for Further Research 22 3.5 Pollination (R.A. Lass) 23 3.6 Replanting and Rehabilitation of Old Cocoa Farms 24 (R.A. Lass) Partial Replanting Method 25 Complete Replanting after Clear Felling 25 Phased Farm Replanting 25 The "Turrialba " Method or Planting under Old 25 Cocoa Trees - vi - Rehabilitation of Existing Trees 26 Chupon Regrowth 27 Coppicing 27 3.7 Priorities for Research 27 Agronomy 27 Physiology 28 Rehabilitation 28 IV. SELECTION AND BREEDING 29 4.1 Prespectives 29 4.2 Genetic Resources and Breeding in Cocoa 30 (G.Lockwood) Quarantine 31 Breeding Objectives and Methods 31 Variety Evaluation 34 Yield-limiting Factors 35 Future Prospects 36 4.3 Priorities for Research 36 V. PROPAGATION 38 5.1 Perspectives 38 5.2 Seed Production 38 5.3 Vegetative Propagation 41 5.4 Priorities for Research 41 VI. DISEASES OF COCOA 43 6.1 Perspectives 43 6.2 Phytophthora Disease (P.H. Gregory) 44 Control by Fungicide Spraying 45 Breeding Resistant Cultivars 46 Phytophthora as a Cocoa Root Pathogen 46 Speculative Long Term Projects 47 6.3 Witches' Broom and Frosty Pod Rot Diseases 48 (H.C. Evans) Control of Witches' Broom 48 Control of Moniliophthora 49 Brazil 49 Ecuador 49 Conclusions 50 6.4 Vascular-Streak Dieback Disease (C. Prior) 51 Historical Background 51 Distribution 51 Symptoms 51 Life Cycle 52 Epidemiology 52 - vii - Control 53 Quarantine 54 Current Research 55 6.5 Virus Diseases of Cocoa (A.F. Posnette) 56 The Viruses 56 Swollen Shoot Disease 56 Ecological Aspects 57 Virus Resistant Cocoa 58 Future Policy 58 6.6 The Swollen Shoot Eradication Campaign in Ghana 59 (J.M.