destroying the stalks at different dates would have the same effect on the mor- 

 tality of the overwintering weevils. 



1931 - Grossman, E. F. Hibernation of the cotton boll weevil under controlled temper- 

 ature and humidity. Fla. Agr. Expt. Sta. B. 240, 19 p. 



The correlation of temperature and humidity with the emergence from hiber- 

 nation of Anthonomus grandis Boh. being difficult to determine from field or 

 hibernation cage data, a study was undertaken in which uniform temperatures and 

 relative humidity were maintained in artificial hibernation quarters for boll 

 weevils. The technique employed in the experiments is described. A study of the 

 longevity of the weevils is shown in tables. Combined with hibernation cage data, 

 it indicates the possibility of a prolonged period during which the hibernated boll 

 weevil can enter and infest a cotton field. 



About 125,000 weevils were used in the experiments, in temperatures main- 

 tained at 47°F., 60°F., and 81°F., with a relative humidity between 79% and 85%. 

 After 170 days, 20% of 32,000 weevils were living; after 206 days, 15%; and after 

 236 days, 10%. Approximately 0.6% lived 300 days, indicating that when hiberna- 

 tion conditions are favorable, 1 weevil out of each 200 to enter hibernation on 

 October 1st could live long enough to emerge from hibernation on August 1st of 

 the following year. Or, entering on November 1st, they could emerge on Septem- 

 ber 1st, though, as a matter of fact, that majority invaded the cotton fields during 

 June. At 47°F., increased mortality was observed during the first month of dor- 

 mancy and again after a period of several months of a low rate of mortality. The 

 destruction of cotton stalks immediately after harvest not only reduces breeding 

 but also prevents the weevil already in the field from feeding enough to withstand 

 an extended period of hibernation. 



1931 - Grossman, E. F. Winter survival of immature stages of the boll weevil. Fla. 

 Ent. 15(1):13-14. 



Field and laboratory investigations in 1927 and 1928 indicate that in Florida 

 the larvae of Anthonomus grandis Boh. in cotton squares and bolls probably fail 

 to develop into adults during the winter months. Though individuals in the late 

 pupal stage in squares and bolls may do so, the toughness of the overwintered 

 bolls generally tends to prevent their emergence. Abandoned cotton stalks should, 

 however, be destroyed early in the autumn, as they provide favorable hibernation 

 quarters for the adult weevils. 



1931 - Grossman, E. F., and P. W. Calhoun. Determination of the winter survival of the 

 cotton boll weevil by field counts. Fla. Agr. Expt. Sta. B. 233, 47 p. 



During several years' observations in Florida, data obtained from hiberna- 

 tion cages on the winter survival of Anthonomus grandis Boh. and on its period of 

 emergence were very inconsistent. They failed to show a seasonal uniformity of 

 emergence under the same weather conditions as occurred in field tests. Data 

 from field counts were uniform; each year's results corresponded with those 

 of the previous or following years. Field counts conducted in 5 different localities 

 in the State also gave uniform results. 



The time of appearance of the weevils rarely extended over a period of 30 

 days, whereas that in hibernation cages lasted over a period of 5 months. The 

 peak of emergence in the field extended from June 3d to the 20th, whereas in the 

 cages it occurred from March 5th to June 2d. The appearance of the weevils in 

 the field seems to be dependent on temperature conditions during May and June, 

 regardless of the conditions prior to that time. Field counts indicate the per- 

 centage of survival and degree of infestation that can be expected from year to 

 year, and from these observations it appears that the weevils enter cotton fields 

 in infested areas during June. 



1931 - Rude, C. S. Cotton boll weevil has no hibernation in Laguna District of Mexico. 

 J. Econ. Ent. 24(3):76l -762. 



In a district of north-central Mexico, a newly emerged adult of Anthonomus 

 grandis Boh. was found on February 17th among cotton bolls picked the pre- 

 ceding autumn. Three live pupae were also discovered while dry cotton bolls were 

 being cut open on February 28th, and 2 old weevils were taken on March 16th 



143 



