10 



CIRCULAR 356, U. S. DEPT. OF AGRICULTURE 



EXPERIMENT 3 



For the third experiment traps were placed in 3,125,000 cubic feet 

 of Turkish tobacco storage warehouses of the closed type. The 

 experiment was started on May 12 with 11 suction light traps, and 

 this number^was increased dining the season until a maximum of 64 

 traps were in operation. The data on the catches, including the 

 temperature for each period, are presented in table 3 and figure 9. 



The catches in table 3 show that the infestation was heavier in the 

 closed than in the open Turkish-tobacco storage (tables 1 and 2). The 

 largest average catch, 954,619 beetles per trap, was made during the 



1,000 

 950 



900 

 850 



800 

 750 

 700 



650 

 600 

 550 

 500 

 450 

 400 

 350 

 300 

 250 

 200 

 I 50 

 100 

 50 



• MAXIMUM TEMPERATURES 

 "oMINIMUM TEMPERATURES' 



♦ 



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100 



90 



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60 



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, 26 ,9 23 



MAY Uu~NfE 



7 17 24 7 21 28 7 9 



JULY 



AUG. 



13 20 29^ 

 OCT. 



SEPT 



Figt/r: 



-Average catches of the cigarette beetle, in relation to the temperature and the season, in closed- 

 storage warehouses containing Turkish tobacco. Experiment 3. 



interval September 9 to 13. During this period 64 traps were oper- 

 ated, or 1 trap for every 48,828 cubic feet. The graph in figure 9 again 

 indicates that beetle migration is seasonal. The largest catch of the 

 spring brood, 90,136 per trap, was made during the 14-day period 

 June 9 to 23, with an average maximum temperature of 90° and an 

 average nrinimum of 62° F. The largest catch was made September 

 9 to^ 13, during the emergence of the third brood, with the average 

 maximum temperature 89° and the average minimum 66°. 



