44 BULLETIN 564, U. S. DEPARTMENT OF AGRICULTURE. 



weevils would be the reduction of their progeny. In practice it is 

 found that two factors serve to prevent the complete elimination of 

 these progeny. These are the eggs deposited by the weevils before 

 capture and the percentage of hibernated individuals actually escaping 

 capture. As has been stated, if undisturbed, the weevils in the Delta 

 usually will produce more than sufficient progeny to cause a maximum 

 crop injury by midsummer. In view of the results of the control ex- 

 periments under heavy infestation conditions, it seems that enough 

 weevils were missed and sufficient eggs were deposited before collection 

 by those actually captured to develop sufficient progeny for a maxi- 

 mum infestation of the crop. 



In view of these considerations, it seems to the writers that in a year 

 of light infestation a slight degree of benefit may be secured from the 

 picking operations, but that in a year of average or heavy infestation 

 this benefit is completely lost. This conclusion is borne out by the 

 experiences of various planters which have come under the observa- 

 tion of the writers, and is especially discouraging in view of the fact 

 that in a year of heavy infestation the control measure is most needed. 



Another point of primary importance in connection with the plan- 

 tation use of these control measures is the labor problem. This 

 requires a consideration of the labor supply available on the average 

 Delta plantation, the labor requirements of the ordinary plantation 

 operations, and the labor requirements of the weevil-picking opera- . 

 tion. In the first place, it is advisable to consider the organization of 

 the labor by which these picking operations are to be conducted. 

 These measures are practiced only on a tenant basis, where a 

 "family" takes care of a certain quantity of land. This land usually 

 is divided between cotton and corn, the greater portion being in 

 cotton. In addition to the labor involved in caring for this land it 

 is necessary for the plantation to levy upon the male members of 

 these families for a certain amount of wage labor to be used in the 

 care of the oat and hay crops, which are handled only on a wage basis. 



RELATION BETWEEN LABOR SUPPLY AND MALARIA. 



The Bureau of Entomology is conducting an investigation on 

 the Hecla plantation, the estate "ffcpi*e one of the writers' tests was 

 conducted, on malaria mosquitoes arra their control. In determining 

 the exact relation of malaria to crop production, Dr. D. L. Van Dine 

 made a detailed analysis of the available and required labor on this 

 plantation. In his published account ' of this work, Dr. Van Dine 

 gives a chart showing the duration of each of the operations involved 



i Van Dine, D. L., "The relation of malaria to crop production." In The Scientific Monthly, November 

 1916, p. 431-439. 



Van Dine, D. L., "The losses to rural industries through mosquitoes that convey malaria." In South- 

 ern Medical Journal, Vol. VUI, No. 3, p. 1S4-194. March, 1915. 



