100 THE MEXICAN COTTON-BOLL WEEVIL. 



SHELTER DURING HIBERNATION. 



Boll weevils in seeking shelter from the cold will enter all kinds 

 of places which might afford shelter. The following statements are 

 quoted from Prof. B. D. Sanderson: 1 



The observations by Prof. Conradi at College Station, Tex., in the early winter of 

 L903, probably indicate some of the normal places for hibernation — that is, under 

 : old cotton brush, and under loose bark. In the hibernation cages, 

 where the weevils were furnished an abundance of rubbish, it was found that many 

 oi them which were hibernating successfully had crawled into the cavities made by 

 borers in dead wood and in similar positions where they were well protected. It has 

 been often noticed that in a wooded country the weevils appear first in spring along 

 the borders of fields next to the woods and gradually work inward from the edges, so 

 thai it .-(.'ems probable that in a wooded country most of them hibernate in woodland. 

 Around outbuildings and barns also are found favorable places, as there is always 

 more or less rubbish and protection in such situations. In 1903 more than five times 

 as many weevils were found in a piece of cotton near the college barn, where cotton 

 had been grown the previous year, than were found in any other locality in that 

 neighborhood. It is also noticeable that weevils are always more numerous near gins 

 than at a distance from them. 



It is noticeable that weevils are much more abundant where cotton is planted in 

 fields where sorghum stubble has been allowed to remain all winter adjoining a last 

 year's cotton field. 



Professor Mally has given the observations of Mr. Teltschick upon finding weevils 

 hibernating in the crevices of the soil around the cotton stalks and roots, at a depth 

 of 3 inches. On March 7, 1901, a raw, windy day, upon 35 stalks, he found 7 live 

 and 2 dead weevils from 1 to 3 inches below the surf ace. In September, 1902, he stated 

 that he had again found weevils in a similar situation during the previous spring, but 

 not as many of them as in 1901. Mr. Teltschick recently writes as follows: 



"I found but few weevils in crevices around stalks during the last two winters, 

 partly because there were no crevices (frequent rains filling them up as soon as formed) 

 and partly because freezes were severe enough to keep cotton from coming out during 

 any part of the last two winters ; whereas in 1900 we had neither rain enough to fill up 

 crevices nor frost enough to keep cotton from budding out at intervals at the base of 

 the stalk, which latter fact accounts, no doubt, for the relatively large number of 

 weevils found within the crevices." 



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 through- 

 out 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 

 fines are exceedingly favorable to tfie hibernation of many weevils, 

 so that it will be found generally true that the worst line of infesta- 

 tion 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, 

 many weevils find favorable shelter in the husks and stalks of the 

 corn. An especially favored place is said by Mr. E. A. Schwarz 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 and in 

 Spanish moss. From such sources the weevils are known to come 

 in large numbers in the spring. Sorghum stubble, which collects 

 debris blown about by the wind, is also very favorable for hibernation. 



1 Bull. G3, Bureau of Entomology, U. S. Dept. Agriculture, pp. 18-19. 



