220 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



have been obtained in connection with the efficiency of trap lights 

 for controlling certain tobacco pests, especially the cigarette beetle. 

 In the tobacco budworm work in Florida it has been demonstrated 

 that a special grade of arsenate of lead is far superior to Paris green 

 and results in a saving of at least $20 per acre. 



Sugar-cane insects. — Work on sugar-cane insects was continued in 

 cooperation with the sugar experiment station of the State of Louis- 

 iana at New Orleans. Practical field tests in the handling of cane 

 trash were continued. A 65-acre poisoning test for the moth borer 

 is now being carried out. 



Much experience has been gained in the transportation of parasites 

 of the cane from Cuba, but the results of the importation have not 

 yet been determined. 



Argentine ant. — The control of the Argentine ant in houses, 

 warehouses, factories, and yards has been greatly facilitated by the 

 development of a new poisoned sirup. This has been satisfactorily 

 used at Hattiesburg, Miss., and Augusta, Ga. A bulletin on this 

 phase of the work was prepared. 



INVESTIGATIONS OF INSECTS AFFECTING THE HEALTH OF MAN. 



The work on insects affecting the health of man dealt with the 

 mosquitoes which transmit malaria, and their control, with the house 

 fly and insects frequenting packing houses, and with the eradication 

 of the Eocky Mountain spotted-fever tick. 



Mosquitoes and malaria. — The work on malaria mosquitoes was 

 continued at Mound, La. This work is directed mainly toward the 

 study of the life histories and habits of the malaria mosquitoes, but 

 considerable attention was directed to the plantation conditions which 

 bring about infection by the disease. The more intelligent classes 

 can obtain practical protection by proper screening and by avoiding 

 foci of infection away from home, but the greatest loss of time occurs 

 in the tenant class. Measures are being evolved to meet plantation 

 conditions in a practical manner. A demonstration of the carrying 

 of malaria by a species of Anopheles hitherto considered a noncarrier 

 was made in cooperation with the Tulane school of medicine. This 

 discovery opens up new problems in control. Studies of the biology 

 of the various species of Anopheles in relation to the malaria organ- 

 ism are being continued. The cooperative work with the Bureau of 

 Fisheries with regard to mosquito control by top minnows has been 

 continued and extended. 



Rocky Mountain spotted fever. — The control work against the 

 Eocky Mountain spotted-fever tick has been continued in the Bitter 

 Boot Valley of Montana during the season of tick activity from 

 March to July, 1916. The general plans of the project have been 

 followed substantially as in the two preceding seasons, with, how- 

 ever, somewhat of a departure in the control program. This con- 

 sisted in the substitution of a " starvation " plan in one of the 

 control districts for the previously recommended dipping and hand 

 picking of domestic animals in the tick-infested zones, and the suc- 

 cess of the substitution has been encouraging. This plan consists 



