104 



At Victoria a series of observations begun on November 11 showed 

 that there was a decided falling off in the number of weevils to be 

 found in the fields between November 20 and December 8. Between 

 November 11 and 19 five examinations, covering a total of 8,157 

 squares, showed that at that period one square in nine, or 11 per cent 

 of the squares, sheltered an adult weevil. By December 8 an exami- 

 nation of 2,000 squares showed that the percentage had fallen to 6. 

 At Victoria, therefore, it is evident that the burning of stalks should 

 have been practiced not later than November 15 to 20. This period 

 followed closely the occurrence of the first light frost on November 

 12, 1904, and it is probable that some such general relationship to tem- 

 perature conditions may be established. The following average mini- 

 mum and mean average temperatures prevailed: 



Date. 



Mean 

 average. 



Average 

 minimum. 





°F. 

 62.2 

 59.3 

 63.9 

 55.6 



°F. 

 51.8 





44.3 



November 19 to 30 



55.0 



December 1 to 10 



46.4 







Apparently weevils will begin to enter hibernation any time after the 

 mean average temperature falls below about 60° F. 



SHELTER SOUGHT IX HIBERNATION. 



Hibernating weevils are to be found in many situations in the field. 

 Where the cotton stalks are allowed to stand throughout the winter 

 they furnish the weevils both the means of subsistence late in the fall 

 and an abundance of favorable hibernation places throughout the field. 

 The prospects of successful hibernation are thereby multiplied many 

 times; and, furthermore, the weevils are already distributed over the 

 field when they first become active in the spring. The grass and 

 weeds which almost invariably abound along fence lines are exceed- 

 ingly favorable to the successful hibernation of many weevils, so that 

 it will be found^generaliy true that the worst line of infestation in 

 the spring proceeds from the outer edges of the field inward. Where 

 cotton and corn are grown in adjacent fields, or where, as is sometimes 

 the case, the two are more or less mixed in the same field, mairy wee- 

 vils find favorable shelter in the husks and stalks of the corn. An 

 especially favored place is said to be in the longitudinal groove in the 

 stalk and within the shelter of the clasping base of the leaf. Perhaps 

 the most favorable of all hibernating conditions are to be found among 

 the leaves and rubbish abounding in the edges of timber adjoining 

 cotton fields. From such places the weevils are known to come in 

 large numbers in the spring. The timber fringes present greater 

 difficulties in the way of removing the favorable conditions than do 

 rtij of the other places mentioned. 



