UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 1032 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



^X^'^^rt- 



Washington, D. C. 



April 25, 1922 



THE BLACKHEAD FIREWORM ^ OF CRANBERRY ON THE 



PACIFIC COAST. 



By H. K. Plank,^ Scientific Assistant, Fruit Insect Investigations, in cooperation 

 with the Washington Agricultural Experiment Station. (With technical 

 description by Cael Heineich, Bureau of Entomology..) 



CONTENTS. 



Page. 



Introduction 1 



Importance of the blackhead 



flreworm 2 



The cranberry industry on the 



Pacific coast 2 



Features of bog- management — 3 

 Phenology of the cranberry on 



the Pacific coast 3 



Introduction of the blackhead flre- 

 worm into the Northwest 4 



Distribution 5 



Food plants - 5 



Destructiveness 5 



Number of generations 6 



Description of stages and habits 7 



Egg 7 



Larva 9 



Pupa 14 



Description of stages and habits — Con. 



Adult 16 



Seasonal history 19 



Natural enemies 20 



Parasites 20 



Predacious enemies 21 



Control experiments 22 



Miscellaneous spraying experi- 

 ments 22 



Demonstration spraying- experi- 

 ments 26 



Recommendations for control 34 



Reflowing 84 



Spraying 34 



Summary and conclusions 37 



Systematic description of Rliopohotw 



naevana Hiibner 42 



Explanation of plates 45 



INTRODUCTION. 



Numerous complaints from Washington cranberry growers, re- 

 ceived by the Bureau of Entomology and the State College of Wash- 

 ington, led the two institutions to make a cooperative investigation 

 of cranberry pests in the Pacific Northwest in 1918 and 1919. In 

 this joint undertaking the writer represented the Bureau of Ento- 



^ Rhopohota naevana Hiibner; order Lepldoptera, family Olethreutidae. Determined by 

 Carl Heinrich, of the Bureau of Entomology. 



2 Appointed Collaborator, Tropical and Subtropical Fruit Insect Investigations, July 1, 

 1920. 



74890°— 22 1 



