UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 1032 
Contribution from the Bureau of Entomology ^Hr^vLS^* 
L. O. HOWARD, Chief ^?*^S. 
Washington, D. C. 
April 25, 1922 
THE BLACKHEAD FIREWORM 1 OF CRANBERRY ON THE 
PACIFIC COAST. 
By H. K. Plank, 2 Scientific Assistant, Fruit Insect Investigations, in cooperation 
with the Washington Agricultural Experiment Station. (With technical 
description by Cael Heinrich, Bureau of Entomology..) 
CONTENTS. 
Page. 
Introduction 1 
Importance of the blackhead 
fireworm 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 fire- 
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 
Page. 
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 34 
Spraying 34 
Summary and conclusions 37 
Systematic description of Rhopobota 
naerana 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- 
1 Rhopobota naevana Hiibner; order Lepidoptera, 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 
