28 FARMERS BULLETIN 848, 



It is sometimes claimed that the use of a crossbar will cause many 

 of the adult weevils to be knocked to the ground, where they will be 

 destroyed by heat. In repeated experiments in jarring and beating 

 cotton plants in which known numbers of weevils were found it was 

 ascertained that very few, if any, left the plants by reason of any 

 agitation that would not break the branches or bark the stems. Occa- 

 sionally, however, a weevil passing over a leaf is jarred to the ground. 

 Entirely too much stress is often placed upon the importance of 

 jarring the adult weevils to the ground. ^Vlien specimens are col- 

 lected by hand and thrown on the surface of the ground, especially 

 if it be finely pulverized, the great majority will be killed almost 

 instantly by the heat. Tliis has caused the mistake on the part of 

 careless observers of supposing that many weevils could be MUed by 

 jarring them to the ground. The difficulty, as pointed out, is that it 

 is totally out of the question to jar more than one weevil out of many 

 hundreds to the ground by any process that would not injure the 

 plants severely. 



The possibility of controlling the boU weevil ])y the hand picking 

 of weevils and infested squares has been discussed extensively. The 

 practice is followed by many planters, while perhaps as many others 

 who have tested it have become convinced of its impracticability 

 and have abandoned it. 



In order to obtain exact data on hand picking, the Bureau of 

 Entomology has performed many experiments. The origmal one 

 was conducted on the lower Colorado River, in Texas, on a planta- 

 tion worked by convict labor, giving the best conditions in the 

 control of labor. No benefit followed thorough pickings twice each 

 week for two months. In another experiment at Gurley, Tex., 

 more than 40,000 weevils were picked on an area of eight acres by 

 paid labor, beginning in April and continuing until July. On the 

 eight acres where this work was done a crop of about 50 pounds per 

 acre in excess of that on other areas was obtained. This was not 

 sufficient, however, to pay for more than a very small fraction of the 

 work done. Later very carefully conducted experiments were per- 

 formed in northern Louisiana, sometimes in j^ears of great weevil 

 abundance, and sometimes when the insects were comparatively 

 scarce. It was not found that the most thorough hand picking of 

 weevils and squares under supervision was effective in reducing the 

 weevils to the extent that the crop was benefited thereby. 



The most important consideration in connection with the hand 

 picking of weevils is the supply of labor. Within the last few years, 

 especially in regions invaded by the boU weevil, the diversification of 

 crops has received a great impetus. Areas of increasing size on 

 most of the plantations are devoted to corn and various forage 



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