. Bulletin of the Department of Agriculture. Agriculture. J^^'^U. Washington, D. C. May 31,1920 CHRYSANTHEMUM MIDGE.^ By C. A. Weigel and H. L. Sanford, Collaborators, Tropical and Subtropical Fruit Insect Investigations. CONTENTS. General description 1 Historical 2 Distribution in the United States and 3 Varieties affected 4 Economic importance 4 Technical description 6 Page. Life history and habits 7 Natural enemies 13 Experiments in control 14 Summary of control and recommendations 21 Preventive measures 22 Literature cited 23 GENERAL DESCRIPTION. The chrysanthemum midge, Diar
. Bulletin of the Department of Agriculture. Agriculture. J^^'^U. Washington, D. C. May 31,1920 CHRYSANTHEMUM MIDGE.^ By C. A. Weigel and H. L. Sanford, Collaborators, Tropical and Subtropical Fruit Insect Investigations. CONTENTS. General description 1 Historical 2 Distribution in the United States and 3 Varieties affected 4 Economic importance 4 Technical description 6 Page. Life history and habits 7 Natural enemies 13 Experiments in control 14 Summary of control and recommendations 21 Preventive measures 22 Literature cited 23 GENERAL DESCRIPTION. The chrysanthemum midge, Diarthronomyia Tiypogaea (F. Low), is a European insect which gamed entrance into the United States a few years ago and smce then has been reported as injurious from widely separated localities in this country and Canada. When chrysanthemums are infested by this midge, the attention of the casual observer is most likely to be drawn to the presence of galls. These galls occur on the leaf, stem, or flower head of the chrysanthemum plant. (See PL I, B and C.) After the larvse hatch from the orange-colored eggs, which are deposited by the adult female on the surface of tender tips and new growth, they bore their way into the tissues, thereby givmg rise to the galls. The galls are cone-shaped and generally project obliquely from the surface. The length of the gall when fully developed is about one- 1 The account of the chrysanthemum midge contained in this bulletin is the result of an investigation which was undertaken with the intention of providing fiurther data on the life history and habits of this insect, as well as more satisfactory means of control. The preliminary life-history studies which were started in February, 1917, by A. D. Borden, of the Bureau of Entomology, were subsequently taken up by H. F. Dietz, of the Federal Horticultiu-al Board. Further studies on life history and control were inaugurated and carried to completion by the writers as a result of the many inquiries
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