Report of the Chief of the 
Bureau of Entomology and Plant Quarantine 
Agricultural Research Administration, 1951 
United States Department of Agriculture, 
Washington^ D. C, September 15, 1951. 
Dr. P. V. Cardox, 
Agricultural Research Administrator. 
Dear Dr. Cardox : This year has been a very active one for the 
Bureau. We were confronted with some of the most difficult ento- 
mological problems of a generation. At the same time a major re- 
organization to strengthen our control and regulatory activities was 
initiated. In addition, much was accomplished in entomological re- 
search. High lights of these activities and accomplishments are re- 
corded in the following report for the fiscal year ended June 30, 1951, 
Sincerely yours, 
Avery S. Hoyt, 
Chief. 
CONTENTS 
Page 
The year in brief 5 
Cotton insects 7 
Supercrop of boll weevils causes huge cotton losses 7 
Insecticides used in vast quantities 7 
Community-wide experiments increase quantity and improve quality 
of cotton 8 
Many insecticides effective against boll weevil 8 
Control of thrips increases yield of seed cotton 9 
Boll worms checked by control measures against boll weevil. 9 
Causes of seasonal decline in effectiveness of insecticides studied 10 
Bureau sponsors conference on cotton insects 10 
Cotton leaf worm extends its range 11 
DDT still outstanding for control of pink bollworm 11 
Pink bollworm quarantine and control continued 12 
Late stalk destruction causes widespread infestation 12 
Record infestations found in 1950 cotton crop 12 
Xoncotton zones established in Louisiana 13 
Control by insecticides demonstrated to growers 13 
Quarantine procedures modified 13 
Quarantine-enforcement activities about normal 14 
Control activities in Mexico parallel those in United States 14 
Eradication of wild cotton lessens threat to Cotton Belt 14 
Forest insects 14 
All-out war waged against Engelmann spruce beetle in Colorado 14 
DDT spray from helicopter controls white pine weevil 15 
DDT spray from helicopter controls pine reproduction weevil 15 
Cheaper and more effective methods developed for airplane-spray 
experiments 15 
Benzene hexachloride widely accepted by lumber industry for con- 
trol of ambrosia beetles . 16 
1 
