Washington, D. C. July 10, 1924 
THE EUROPEAN ELM SCALE IN THE WEST.’ 
By Frank B. HeErsert, Scientific Assistant, Forest Insect Investigations, 
Bureau of Entomology. 
CONTENTS 
Page. | Page. 
RMAEMAT HE 1 Life history and habits__________ 9 
OLD UU ME G2 Se el 1 Seasonal history —_ Ps - ae P 11 
eus¢pry-=- - 3s ee eee 2 | Natural enemies__________ Vee 12 
Synony my es Fe Control expermments 2 a SE 13 
Distribution and spread at ee _ 5 | Recommendations for control ______ 15 
i a pitoios ppetan FT oy nary 8 = eon ae 17 
Food plants_______ 2G Falher ee ie). akteree Cited 3 oe ae Fee er 18 
_ ISSR aa 6 | 
INTRODUCTION. 
The European elm scale, Gossyparia spuria (Modeer), has long 
been known in Europe and the Eastern United States as a serious 
enemy of the elm. It was first discovered in the West in 1893, when 
E. M. Ehrhorn found it infesting elms on the Stanford University 
campus, Palo Alto, Calif. Prompt measures of eradication were 
attempted, but were not entirely successful. Since that time it has 
spread from this or other sources until it is now quite widely dis- 
tributed throughout the West. It is becoming of considerable impor- 
tance as a shade-tree pest owing to its distribution and to its par- 
ticularly aggressive habits in newly infested localities. 
IMPORTANCE. 
The elm is probably the most popular shade tree in America. It 
attains good size, produces a luxurious amount of green foliage, and 
is planted throughout the United States and elsew here in dooryards, 
along streets, and in parks for shade and ornament. In the East 
t Acknowledgments are due to Dr. A. D. Hopkins, Ferest Entomologist: H. FE. Burke, 
Specialist in Forest Entomology : Harold Morrison, Coccidologist; and others, for helpful 
suggestions and observations; to W. S. Fisher, Specialist in Forest Coleoptera, for identi- 
fication of the coccinellid predators : to S. B. Doten, Director and Entomologist of the 
Nevada Agricultural Experiment Station, and to Frank N. Wallace, State Entomolcgist of 
Indiana. for the use of a number of illustrations used in this publication, 
? Resigned June 30, 1920. 
69577°—24——__1 
