BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. 



23 



Table XII.- 



-Summary of development of first generation boll weevils under- 

 field conditions on upland cotton. 



Date of oviposi- 



Date squares 

 dropped off. 



Date hatched. 



Total num- 

 ber weevils 

 bred. 



Average period of 

 development. 



Mean 

 air 

 hu- 

 mid- 

 ity. 



Mean 

 soil 

 tem- 

 pera- 

 ture. 



Aver- 

 age 

 maxi- 

 mum 



tion. 



Male. 



Fe- 

 male. 



On 

 plant. 



On 

 ground. 



To- 

 tal. 



soil 



tem- 

 pera- 

 ture. 



May 29- June 1... 

 May 29- June 21.. 

 May29-June5. .. 

 June 1- June 14... 

 June 2- June 8... 

 June 8- June 15.. 

 June9to Junel3. 

 June6-Junel4... 

 June8-Junel9... 

 Junel2-June21.. 

 Junel2-June23.. 

 June 18- June 22.. 



June 6- June 25. 

 June 7- July 8... 

 June 9- June 16. 

 Junell-June24 

 ,Tunell-June23 

 June 16- June 30 

 Junel8-June23 

 June 17- July 1.. 

 June 16- June 30 

 Junel8-July4. . 

 June 19- July 8.. 

 June30-July8.. 



Junel7-June25. 

 June 12- July 10. 

 June20-June25. 

 June20-July 5. . 

 June22-June25. 

 June 30- July 5.. 

 July 2- July 5... 

 July 3- July 9... 

 July 1- July 5... 

 July 5- July 10.. 

 July2-Julyl3.. 

 July 11- July 13. 



8 

 15 

 7 

 8 

 2 

 5 

 1 

 7 

 5 

 6 

 5 

 4 



6 

 7 

 3 

 3 

 

 4 

 3 

 3 

 4 

 7 

 7 

 5 



Days. 

 11.6 

 11.2 

 10.8 

 11.2 

 11 



10.1 

 11.5 

 10.3 

 10.4 

 9.3 

 12 

 12.5 



Days. 

 10.1 

 10.8 

 9.4 

 12.7 

 10.5 

 12.2 

 11.0 

 13.7 

 13.3 

 12 

 11.8 

 9.4 



Days. 

 21.7 

 22 

 21.2 

 23.5 

 21.5 

 22.3 

 22.5 

 24 



23.7 

 21.3 

 23.8 

 21.9 



65.5 



72.2 



65.2 



76.3 



62.5 



76.3 



76.3 



75.96 



76.3 



77.2 



79.2 



79.2 



85.4 



82.3 



85.5 



81 



85.5 



81 



81 



81.4 



81 



82.3 



82.8 



82.8 



111.7 

 101.6 

 109.7 

 101.6 

 109.7 

 101.6 

 101.6 

 101.3 

 101.6 

 101.6 

 101.2 

 101.2 



Total 



73 



52 







1 







Weighted aver- 

 age. 







10.9 



11.4 



22.4 73.51 



82.6 



103.7 

















DEVELOPMENTAL PERIOD OF FIRST GENERATION BOLL 

 WEEVILS ON SHORT STAPLE UPLAND, SEA - ISLAND, AND 

 LONG-STAPLE UPLAND COTTONS UNDER FIELD CONDITIONS. 



In addition to the series of hibernated female weevils under obser- 

 vation a series of first generation weevils was used to determine the 

 difference in the length of the developmental period under field con- 

 ditions on upland, sea-island, and long-staple cottons. 



The first generation female weevils deposited eggs at an average 

 rate of 7.6 eggs per day on sea-island cotton. The maximum number 

 of eggs deposited during any one day in sea-island cotton squares 

 was 29. 



The 10 female weevils under observation on long-staple cotton 

 squares deposited eggs at an average rate of 6.3 eggs per day. The 

 greatest number of eggs deposited during one day in long-staple 

 squares was 21 eggs. 



On upland cotton the 10 female weevils deposited eggs at an aver- 

 age rate of 6.2 eggs per day, with a maximum of 23 eggs deposited 

 by a single female during one day. 



On upland cotton the infested squares remained on the plants for 

 an average period of 10.9 days. A period of 11.4 days was the 

 average time required to complete the development of the immature 

 stages after infested squares dropped off the plant. 



The average number of days elapsing from the date of egg punc- 

 ture to the falling of the infested squares was 10.7 on sea-island 

 cotton. The average number of days required to complete the de- 



