17 



that from 60 to 78 per cent of the eggs deposited in cotton fields 

 are placed elsewhere than on the squares and flowers. 



Immediately upon hatching the young larva usually devours the 

 eggshell from which it emerged. It then begins a restless search 

 for food, wandering aimlessly about, and now and then eating 

 a tiny portion of the epidermis of the plant. Often these actions 

 are continued for hours, many of the delicate larvae perishing before 

 suitable food is found. The minute larvse are unable to enter any 

 but the most tender portions of the plant ; consequently those hatch- 

 ing from the large percentage of eggs which are not placed on the 

 tender squares, flowers, and small bolls crawl about and feed to a 

 greater or less extent upon the surface of the plant until such 

 portions are found. 



A number of observations were made during August, 1905, upon 

 larvae hatching from eggs deposited on squares and flowers. The 

 six larvae under observation averaged about forty minutes in crawl- 

 ing about and feeding before the squares or flowers were entered — 

 an ample time for them to have eaten suflftcient poison to have 

 destroyed them had these portions of the plant been thoroughly 

 dusted with Paris green. Hence it appears, from various observa- 

 tions, that it would be theoretically possible to destroy about 90 

 per cent of the larvae at the time of hatching, if the plants were 

 kept continuously and thoroughly covered with Paris green. The 

 impossibility of maintaining poison continuously upon all parts of 

 the plants during the entire period of egg hatching is obvious. 

 However, practical tests of poi.soning cotton (see pp. 25-27) indicate 

 that satisfactory results may be obtained by making from 1 to 3 appli- 

 cations of Paris green or other arsenical poison at the proper time. 



No arbitrary date for the application of poison may be given on 

 account of the variability of the time at which the larvae begin to 

 hatch in destructive numbers in different localities and seasons. Moths 

 are seldom seen in cotton fields until the third generation appears, 

 which is usually from July 20 to August 5. When moths in large 

 numbers are seen flying about the fields in the evening it may be taken 

 for granted that oviposition is taking place and the poison should be 

 applied within three or four days. 



As regards the dusting and spraying methods, the former is usually 

 more practicable, owing to the difficulty often experienced in securing 

 water in proximity to the fields and the greater time required in 

 applying poison in liquid form. 



The bag and pole method of application is fairly efficient and obvi- 

 ates the purchase of machinery. Geared machinery may be secured 

 to apply poison either in the dust or spray form. The expense of 



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