. Bulletin of the Department of Agriculture. Agriculture. m BULLETIN No. 616 Contribution from the Bureau of Entomology L. O. HOWARD, Chief. Washington, D. C. PROFESSIONAL PAPER February 14, 1918 THE CITRUS THRIPS. By J. R. Hoeton, Tropical and Subtropical Fruit Insect CONTENTS. Page. Introduction 1 History and distribution 2 Nature and extent of injury 3 Dissemination ^ 7 Food plants 8 Life history and habits 10 Page. Seasonal history 22 Natural checks 24 Natural enemies _^ 25 Control experiments 29 Bibliography 41 INTRODUCTION. The citrus thrips [Scirtothrips2 (Euthrips
. Bulletin of the Department of Agriculture. Agriculture. m BULLETIN No. 616 Contribution from the Bureau of Entomology L. O. HOWARD, Chief. Washington, D. C. PROFESSIONAL PAPER February 14, 1918 THE CITRUS THRIPS. By J. R. Hoeton, Tropical and Subtropical Fruit Insect CONTENTS. Page. Introduction 1 History and distribution 2 Nature and extent of injury 3 Dissemination ^ 7 Food plants 8 Life history and habits 10 Page. Seasonal history 22 Natural checks 24 Natural enemies _^ 25 Control experiments 29 Bibliography 41 INTRODUCTION. The citrus thrips [Scirtothrips2 (Euthrips) citri Moul.] has caused more or less injury to oranges, grapefruit, and lemons in California for the last 20 or 25 years. Owing to its minute size the insect re- mained undiscovered for many years, and its injury to the fruit was attributed to other causes, such as wind whipping, freezing, etc. About the year 1908 the injury became so severe in Tulare County that the old theories began to be doubted and the need of expert in- vestigation was realized. The preliminary examination in behalf of the Bureau of Entomology was made by Dudley Moulton (2)3 and resulted in a description of the insect and its injury. Subsequently the bureau undertook a thorough investigation of the life history and control of the insect, this project being started at Lindsay, Tulare County, Cal., in 1909. A report of progress by Jones and Horton (5) and a Farmers' Bulletin on the control of the thrips by the writer (15) have appeared since. 1 Transferred to Cereal and Forage Insect Investigations, October 1, 1917. 2 Hood (14) places this insect in the genus Scirtothrips on the apparently adequate grounds that the thorax is finely, transversely striate and the abdomen clothed with minute hairlike processes. 8 See Bibliography, p. 41. 13138°—IS—Bull. 616 1. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appea
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