INSECTS INJURIOUS TO COTTON 253 



poison be -applied first when the first squares appear and that five 

 applications be given at weekly intervals. The poison must be 

 applied by hand with a powder-gun so that it is blown into the 

 squares. The first application requires about 2J pounds per acre 

 and the last 5 to 7 pounds. Since that time there has been a 

 very considerable amount of experimental work on boll weevil 

 poisoning and opinions as to the value of the treatment have been 

 variable. All authorities seem now to agree that poisoning with 

 arsenate of lead or of calcium, applied in the form of a dust, is 

 a valuable means of protection from the weevil, somewhat more 

 favorable results having been secured from the arsenate of lead 

 than from the calcium arsenate. The number of treatments and 

 the amount of material used will vary somewhat with the infesta- 

 tion and local conditions but eight pounds per acre has been used 

 with profit. Professor Newell puts special-emphasis on applying 

 the material so that it will cover the squares, bolls and terminal 

 buds rather than the foliage.* 



The Pink Bollworm f 



An insect which might become of the greatest importance to 

 the cotton industry is the pink bollworm, now present in this 

 country in only small areas in 

 Texas and Louisiana and being 

 eradicated in that area by vigor- 

 ous measures prosecuted by the 

 Bureau of Entomology of the 

 United States Department of Agri- 

 culture, which also maintains a 

 strict quarantine to prevent the 

 spread, even prohibiting the grow- 

 ing of cotton in certain counties 

 in order to form a barrier to prog- 

 ress by creating a belt where no 

 food can be secured by the insect. FIG. 217. The pink bollworm (Pec- 

 The pink bollworm is probably * '$^J& 

 a native of southern Asia and Research, Vol. IX, No. 10.) 



* See Newell and Smith, "Circular 33, La. Crop Pest Comm., ad Newell 

 and Bynum, Jour. EC. Ent., Vol. 13, No. 1, 1920; also B. R. Goad, U. S. 

 Dept. Agr., Bulletin 731. 



t Pectinophora gossypiella Saunders. Family Gelechiidce. See W. D. Hun- 

 ter, Bulletin 723, U. S. Dept. of Agr. 



