90 HIBERNATION OF THE COTTON BOLL WEEVIL. 



14 days; the average 6.9 days. The maximum of the individuals 

 emerging in March was 51 days; the average 16.9 days. For the 

 April-emerging weevils the maximum was 46 days; the average 21.2. 

 For the May-emerging weevils the maximum 33 ; the average 15.8 days. 

 Of the June-emerging weevils maximum 12 days; the average 7.4. It 

 will be seen that even in such an abnormal season as 1907 weevils 

 emerging any time during the month of May might be expected to live 

 for at least 15 days and individuals emerging at any time during the 

 month of June to live for more than 7 days. It is thus clear that many 

 weevils emerging in May would survive without any food whatever 

 until considerably after the middle of June and that those of the June 

 emergence would survive in many cases beyond the first of July. 



It is important to note that a considerable percentage of the 

 emerging weevils did not appear until late. For instance, 10.2 per 

 cent of all the weevils which survived at Calvert did not appear 

 until between May 10 and June 6. At Dallas the percentage for this 

 period was 7.5, and at Victoria, 2.38. 



The observations on the longevity of the fed weevils also has a bear- 

 ing on late planting, since there is always some volunteer cotton 

 around seed houses and elsewhere that will be found by the weevils. 

 The maximum length of life of the fed weevils which appeared in 

 February was 47 days, the average 45 days; of March-appearing 

 weevils the maximum 93 days, average 45.5 days; of April-appearing 

 weevils maximum 82 days, average 46.5 days; of May-appearing 

 weevils maximum 86 days, average 55 days; of June-appearing 

 weevils maximum 46 days, average 37.8 days. 



The longevity of the weevils emerging in May and June is most 

 important. The average survival of 55 days in one case and the 37.8 

 in the other shows that with such food as can easily be obtained, at 

 least some of the emerging weevils would be carried over until far 

 into the summer, even if no cotton were planted. 



The records just referred to are, of course, a sufficient refutation of 

 the theory that the weevil could be ''starved out" by late planting. 

 It has been proposed, however, that the number of weevils surviving 

 to damage late-planted cotton would be relatively so small that such 

 cotton would have a better chance to mature a crop than that planted 

 earlier. In order to test this matter the Bureau of Entomology has 

 conducted practical field tests in which cotton has been planted 

 about the 10th of June. In one season four of these experiments were 

 performed in parts of Texas showing distinct climatic features and one 

 in Louisiana in cooperation with the State Crop Pest Commission. In 

 every case the yield was cut down so severely by the weevils that 

 survived the prolonged period in which no cotton was to be found 

 that the impossibility of preducing cotton in that way was fully 

 demonstrated. 



