UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 875 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



July 20, 1920 



COTTON BOLL WEEVIL CONTROL BY THE USE 



OF POISON. 1 



By B. R. Coad, Entomological Assistant, and T. P. Cassidy, Cotton Entomolo- 

 gist, Southern Field Crop Insect Investigations. 



CONTENTS. 



Page. 

 Principles governing poisoning op- 

 eration 1 



Kind of poison to use 3 



Poison specifications required — 3 



Send samples of calcium arse- 

 nate for analysis 4 



Use of mixtures not recom- 

 mended 4 



Supply of calcium arsenate and 



dusting machinery available- 4 



Keeping qualities of calcium ar- 

 senate 5 



Effect, of the poison on man and 

 animals 5 



Plant injury by calcium arse- 

 nate . 6 



How to apply poison 8 



Amount required per acre for 

 each application 8 



Conditions under which to make 



applications 9 



Arrangement of poisoning sched- 

 ule 9 



Season for applications 10 



Time of starting poisoning 11 



Time interval between applica- 

 tions 12 



Number of applications 14 



Time to stop poisoning 14 



Page. 



How to apply poison — Continued. 

 Effect of rain on an application 



of poison 15 



Starting poisoning in the pres- 

 ence of a complete infestation_ 15 

 Earlier season treatment of 



isolated infestations 16 



Organization of poisoning operation- 17 



Dusting machinery to use 18 



Hand guns 19 



Power dusters 21 



Wheel-traction or cart dusters. 22 

 Need of an intermediate type of 



dusting machine , 23 



Lighting equipment for dusting 



machines 23 



Capacity of machines for treat- 

 ing several rows per trip 24 



Features to he noted in purchasing 



cotton-dusting machinery 24 



Hand gun 24 



Wheel-traction or cart duster 25 



Power duster 26 



Cost of poisoning 26 



Gains to be expected from poisoning-. 26 



Advisability of poisoning under 



present conditions 28 



Control of the cotton leafworm and 

 fall army worm with calcium 

 arsenate 29 



PRINCIPLES GOVERNING POISONING OPERATION. 



IT SHOULD BE UNDERSTOOD that in poisoning for boll- 

 weevil control extermination is not attempted or secured. The 

 result aimed at is a sufficient reduction of the weevil infestation to 

 permit maturing a full crop of cotton. This is brought about by tak- 



1 The investigations upon which this bulletin is based were in a sense the outgrowth 

 of the work of Mr. Wilmon Newell, who published, together with Mr. G. D. Smith, in 

 174542°— Bui. 875— 20- — 1 



