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CIRCULAR 6 3 5, U. S. DEPARTMENT OF AGRICULTURE 



houses that have not been fumigated or in which control has not been 

 obtained because of improper timing, faulty application, or too few 

 applications, a definite schedule based upon trap catches should be 

 adopted and followed. In such storages, where the tobacco moth 

 and the cigarette beetle are present in injurious numbers, at least 

 four fumigations should be performed during the warm seasons. 

 On the basis of the average emergence dates in North Carolina and 

 Virginia, the first application of gas should be made between May 15 



Figure •>:! — Fabrirated-board Light trap used to indicate the emergence of broods of 



stored-tobacco insects. 



and 31. depending upon the rate of emergence of the spring brood 

 as indicated bv trap catches. The second should be applied between 

 June 25 and July 5. the third between August 10 and 25, and the 

 fourth between September 15 and 30. Spring temperatures and the 

 movement of infested tobacco into or out of storage will cause varia- 

 tions in the dates on which fumigation should be made, and the most 

 advantageous time can be determined only through a knowledge of the 

 insect conditions as shown bv trap catches and personal observations 

 Where fumigation and dusting with pyrethrum powder have reduced 

 the moth population to low levels, the early fumigation (May 15 to 



