BIOLOGY OF TOBACCO MOTH AND ITS CONTROL 



27 



The average weekly catch of moths for the period April 11 to 

 October 31 and the average temperatures for each week are shown in 

 table 7. The first moths of the spring brood were collected from the 

 trap indicators in the week which ended April 25. In the week which 

 ended May 30 the average catch of moths per indicator was 270.7, and 

 it was believed that this represented about the peak of emergence of 

 the spring brood. The warehouses were sealed in the manner already 





Figure 19. — Sliding door of a tobacco warehouse sealed with a mixture of asbestos and 

 calcium chloride in preparation for fumigation. 



described and were fumigated on June 1, using a dosage of 10 ounces 

 of hydrocyanic acid per 1,000 cubic feet of storage space and an 

 exposure of 72 hours. Fumigations at this dosage and exposure were 

 repeated in the warehouses on June 28, August 3, and September 8. 

 The total and the average catches of moths per trap for each week are 

 shown in table 7. 



