AN ABSTRACT- OF THE THESIS OF Adama Sy for the degree ofMaster of Science in Entomology presented on June 10, 1977 Title: INSECT PESTS OF ECONOMIC IMPORTANCE ON CEREAL CROPS IN THE SENEGAL RIVER BASIN, WEST AFRICA Redacted for Privacy_ Abstract approved R. E. Berrybnd J. P. iattin Cereal crops cultivated in Mali, Mauritania and Senegal consist primarily of sorghum, millet, rice and maize. They form the gramin- eous crops that, are programmed for the agricultural improvementof the Senegal River Basin. Twelve economically important insect pests on these crops were selected for study and treated with regard to their potential hazard to crop production. The selection of these insect pests was based on entomological investigations carried out in Senegal, Mali and the Senegal River Valley. Information was gathered from similar ecological areas in the Paleotropic region. The following insect pests were selected: Diptera: Atherigona spp (Muscidae), Contarinia sorghicola (Coquillet) (Cecidomyiidae) and Orseolia oryzae (Wood-Mason) (Cecidomyiidae); Lepidoptera: Acigona ignefusalis (Hampson), Chilo zacconius Bleszynski, Maliarpha separa- tella Ragonot (Pyralidae), Heliothis armigera (Hubner), Sesamia calamistis Hampson, Spodoptera exempta (Walker) and Spodoptera littoralis (Boisduval) (Noctuidae); and Orthoptera: Locusta migra- toria migratorioides (Reiche and Fairmaire) and Schistocerca americana gregaria (Forskal) (Acrididae). Information pertaining to the identi- fication, distribution, host-plants, biology and control strategies, including agronomical and mechanical controls, varietal resistance, biological control and chemical control are presented for each pest. The physical environment in the Senegal River Basin and agricultural production of the Senegal River Valley are described. An overall assessment of the pest complex of cereal crops is given and the pre- sent status of insect pest control in the Senegal River Basin is discussed. Insect Pests of Economic Importance on Cereal Crops in the Senegal River Basin, West Africa by Adama Sy A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Completed June 10, 1977 Commencement June 1978 APPROVED: Redacted for Privacy Professor of Entomology in charge of major Redacted for Privacy Head of Department of Entomology Redacted for Privacy Dean of Graduate School Date thesis is presented June 10, 1977 Typed by Kitty Dougherty for Adama Sy ACKNOWLEDGEMENTS My gratitude to Dr. R. Berry and Dr. J. Lattin is far greater than is possible to express. I have benefited from their kindness, support and understanding since my arrival in January, 1973 at Oregon State University. Dr. R. Berry directed my academic training during my undergraduate work and he teamed with Dr. J. Lattin to organize my graduate program. Dr. J. Lattin recognized the need for entomological investigations in areas seldomly known for their entomofauna so as to anticipate entomological problems, and Dr. R. Berry foresaw the necess- ity of a compendium on the economically important insect pests of these areas so as to avoid entomological crisis. They provided the challenge and incentive with which I undertook this project. I am also thankful to Dr. W. Kronstad and Dr. T. Jackson for their valuable suggestions and their kind advice during the preparation of this project. I would also like to extend my grateful acknowledgements to Gretchen Dihoff, Scientific Librarian of the MUSAT: sra Project, University of California, Riverside, and to her assistants for providing free access to the Sahelian literature. My sincere appreciation is also extended to Dr. J. Breniere, Chairman of the Entomology Department of IRAT, Mont- pellier, France; J. Appert, Entomologist at the ORSTOM Centre de Dakar, Senegal; B. Vercambre, Entomologist at the Institut Senegalais de Recherches Agricoles, Bambey, Senegal; Galledou Tahara at the OCLALAV Centre d'Aouin El Atrouss, Mauritania; Kane Hadya and Kane Cire at the Ministry of Rural Development, Nouackchott, Mauritania, and to the Documentation Service of the Organisation pour la Mise en Valeur du Fleuve Senegal (OMVS), St. Louis, Senegal, for the materials and suggestions they kindly provided. I am also indebt to Kitty Dougherty whose kindness and understanding supported the burden of typing this manuscript, and to literally hundreds of authors from whose work I have drawn freely the information presented. TABLE OF CONTENTS Page INTRODUCTION 1 Objectives 3 AGRICULTURE AND ECOLOGY OF THE SENEGAL RIVER BASIN 4 The Senegal River Basin 4 Location 4 Climate 6 Vegetation 8 Soils 10 Agriculture Production 12 Major crops 12 Potential crops 13 Crops and cropping systems 14 Management practices 15 INSECTS OF ECONOMIC IMPORTANCE ON CEREAL CROPS 21 Identity and Distribution of Major Groups of Pests 21 Crop Losses and Current Pest Control 23 Monographs of Selected Important Insect Pests 27 Diptera 27 Atherigona spp. [Sorghum shoot fly] 27 Identification 28 Distribution 29 Hosts 29 Damage 30 Page Biology 31 Control strategies 35 Agronomical and mechanical control 36 Varietal resistance 36 Biological control 39 Chemical control 39 Contarinia sorghicola (Coquillet) [Sorghum midge] 41 Identification 42 Distribution 44 Hosts 45 Damage 45 Biology 47 Control strategies 51 Agronomical and mechanical control 52 Varietal resistance 53 Biological control 54 Chemical control 55 Orseolia oryzae (Wood-Mason) [Rice gall midge] 57 Identification 58 Distribution 59 Hosts 60 Damage 61 Biology 63 Control strategies 66 Page Agronomical and mechanical control 68 Varietal resistance 68 Biological control 70 Chemical control 70 Lepidoptera 72 Acigona ignefusalis (Hampson) 72 Identification 73 Distribution 74 Hosts 75 Damage 75 Biology 76 Control strategies 79 Agronomical and mechanical control 80 Varietal resistance 81 Biological control 81 Chemical control 82 Chilo zacconius Bleszynski 83 Identification 84 Distribution 85 Hosts 85 Damage 86 Biology 87 Control strategies 90 Agronomical and mechanical control 90 Page Varietal resistance 91 Biological control 92 Chemical control 93 Heliothis armigera (HUbner) [Old world boll worm] 95 Identification 97 Distribution 99 Hosts 100 Damage 100 Biology 102 Control strategies 105 Agronomical and mechanical control 106 Varietal resistance 107 Biological control 107 Chemical control 108 Maliarpha separatella Ragonot [Madagascar white rice borer] 110 Identification 111 Distribution 112 Hosts 112 Damage 113 Biology 114 Control strategies 115 Agronomical and mechanical control 117 Varietal resistance 117 Biological control 118 Page Chemical control 118 Sesamia calamistis Hampson [Pink borer] 120 Identification 121 Distribution 122 Hosts 123 Damage 123 Biology 124 Control strategies 127 Agronomical and mechanical control 128 Varietal resistance 128 Biological control 129 Chemical control 130 Spodoptera exempta (Walker) [African Army worm] 131 Identification 131 Distribution 134 Hosts 134 Damage 135 Biology 136 Control strategies 138 Agronomical and mechanical control 140 Varietal resistance 140 Biological control 141 Chemical control 142 Spodoptera littoralis (Boisduval) [Egyptian Cotton worm] 144 Page Identification 145 Distribution 147 Hosts 148 Damage 149 Biology 150 Control strategies 153 Agronomical and mechanical control 154 Varietal resistance 155 Biological control 156 Chemical control 156 Orthoptera 158 Locusta migratoria migratorioides (Reiche and Fair- maire) [African migratory locust] 158 Identification 160 Distribution 163 Hosts 165 Damage 167 Biology 170 Control strategies 174 Schistocerca americana gregaria (Forskal) [Desert locust] 176 Identification 178 Distribution 182 Hosts 183 Damage 184 Page Biology 189 Control strategies 193 Agronomical and mechanical control 196 Varietal resistance 197 Biological control 198 Chemical control 200 CONCLUSIONS 202 BIBLIOGRAPHY 204 LIST OF TABLES Table Page I. Area, Production and Yield of Sorghum and Millet in the Senegal River Valley 17 II. Area, Production and Yield of Rice in the Senegal River Valley 18 III. Area, Production and Yield of Maize in the Senegal River Valley 19 IV. Area and Production of Major Cereal Crops in Senegal, Mali and Mauritania 20 INSECT PESTS OF ECONOMIC IMPORTANCE ON CEREAL CROPS IN THE SENEGAL RIVER BASIN, WEST AFRICA INTRODUCTION The Senegal River Basin is composed of areas distributed in the four West African states of Guinea, Mali, Mauritania and Senegal. Mali, Mauritania and Senegal contain the largest portion of the river basin, including the Senegal River Valley, which is the principal area for crop production. With the exception of Guinea, the states form the western section of the Sahelian zonel, whose fragile ecosystems and vulnerable environments underline the precarious living conditions found there (see MAB technical notes 1975, and Anonymous 1975a). One way to meet the challenge which is imposed by the physical environment is the pooling together of commonly held natural resources. This has been recognized by the Sahelian countries who have set up an agency to formulate regional programs (Comite Inter-etats de lutte contre la secheresse au Sahel-CILSS)2 (Anonymous 1975a). The states of Mali, Mauritania and Senegal have also formed the Organization for De- velopment of the Senegal River (Organisation pour la Mise en Valeur du 3 Fleuve Senegal-OMVS) , whose objectives, among others, are to regulate crop production in the Senegal River Valley. 1The Sahelian zone extends between the Sahara desert in the north and the Sudanic zone to the