62 WEEVIL-RESISTING ADAPTATIONS OF COTTON. 



The feeding experiment reported by Messrs. Hunter and Hinds" 

 shows that weevils fed exclusively upon bolls lived less than twenty 

 days, while those fed upon the squares lived nearly seventy days. 

 The bolls proved to be much less suitable for food than the leaves, on 

 which the weevils were able to prolong life for thirty days and 

 upward, though no eggs were laid on a leaf diet. It may be that in 

 Texas, where the army worms sometimes destroy all the leaves, the 

 weevils might be driven to gnawing the bolls for food, but in Guate- 

 mala the plants remain in full leaf throughout the growing season. 



BACTERIAL DISEASES FOLLOWING WEEVIL INJURIES. 



In the study of the bolls of the Kekchi cotton three diseased con- 

 ditions were observed, some or all of which may be of bacterial 

 origin, the bacteria having been introduced, perhaps, by the weevils 

 at the time of egg laying. Xone of these diseased conditions is fre- 

 quent, and as they do not permit the fruit to reach normal maturity 

 it seems very unlikely that they can be introduced into the United 

 States with the seeds. It may be stated in addition that the seed 

 obtained by Mr. Kinsler in the season of 1905 has been carefully 

 selected in the field and comes from the earliest and most vigorous 

 bolls. 



The first of the diseased conditions consists in a white deliquescence 

 of the immature seeds and lint as though the lock had been dipped in 

 milk. There is also a distinct odor of fermentation. Another dis- 

 ease turns the seed and lint brown. Though observed only in bolls 

 which have been punctured by the weevil, there was often an 

 apparent connection between the disease inside and the large extra - 

 floral nectaries. A column of transparent or somewhat discolored 

 tissue extends from each nectary obliquely upward to the cavity of 

 the boll. This may be a symptom of the disease or it may indicate 

 that bacteria find their way into the bolls by way of the nectaries. 



The third abnormal condition was also indicated by a brown dis- 

 coloration of the wall and contents of the affected compartment of 

 the boll. The seeds and lint soon die and shrivel. No special indi- 

 cation of bacterial activity was noted, and it may be that the death 

 of the weevil egg or larva has some prejudicial effect upon the sur- 

 rounding cells, as suggested by the brown discoloration already 

 noted in describing the effects of proliferation. Such a disturbance 

 might continue to spread and thus cause the death of the young seeds. 



BREEDING IN BUDS A DERIVED HABIT. 



The fact that the weevil larvae are found in the young buds of the 

 cotton plant and also in the full-grown bolls has been taken to mean 

 that it affects all the intervening stages as well. This would imply 



a Hunter. W. D„ and Hinds, W. E. : 1. c. pp. 34-35. 



