. Bulletin of the Department of Agriculture. Agriculture. BULLETIN No. 838 Contribution from tlie Bureau of Entomoiogy L. O. HOWARD, Clilef. Washington, D. C. PROFESSIONAL PAPER June 5. 1920 CYPRESS BARK SCALE.^ By F. B. Herbebt, Scientific Assistant, Forest Insect Investigations. CONTENTS. Economic importance History Native host plant Distribution and spread- Injury Associated insects Food plants Page. 1 2 2 3 4 7 Descriptions Life history and habits Seasonal history Predacious and parasitic enemies- Control experiments Recommendations for control Summary Page. 8 12 16 18 19 20 22 ECONOM
. Bulletin of the Department of Agriculture. Agriculture. BULLETIN No. 838 Contribution from tlie Bureau of Entomoiogy L. O. HOWARD, Clilef. Washington, D. C. PROFESSIONAL PAPER June 5. 1920 CYPRESS BARK SCALE.^ By F. B. Herbebt, Scientific Assistant, Forest Insect Investigations. CONTENTS. Economic importance History Native host plant Distribution and spread- Injury Associated insects Food plants Page. 1 2 2 3 4 7 Descriptions Life history and habits Seasonal history Predacious and parasitic enemies- Control experiments Recommendations for control Summary Page. 8 12 16 18 19 20 22 ECONOMIC IMPORTANCE. The Monterey cypress (Cupressus macrocarpa Hartw.) is one of the most popular shade and ornamental trees in California. It is planted separately or in hedgerows and often trimmed to formal shapes. Due to its thick, spreading habits it makes a good wind- break where it is planted in exposed areas. It is used especially along the coast and in the sandy citrus areas of San Bernardino County. It is also cultivated as an ornamental tree in many other parts of the world. The cypress bark scale infests a large percentage of these trees in California, causing a great deal of injury, particularly to the thickly planted hedgerows (PI. I, figs. 1, 2) and windbreaks. In the San Francisco Bay region it ranks first among the pests of the ^ Ehrhomia cupressi (Ehrhorn). Order Hemiptera, suborder Homoptera, family Coc- cidae. Note.—An investigation of the injury to cypress trees in California was taken up by the writer, at the suggestion of Dr. A. D. Hopkins, Forest Entomologist, in November, 1916. An examination made of these trees in the vicinity of the Los Gatos laboratory disclosed the main cause of the injury to be the cypress bark scale, Ehrhornia cupressi (Ehrhorn). This bulletin contains a record of studies of its history, biology, importance, and control made during this investigation. The writer wishes to acknowledge the assistance of Dr. A. D. Hopkins, Forest Ento- m
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