CONTROL OF INSECTS ATTACKING STORED TOBACCO 



tobacco they may reach their full size (about three-sixteenths of an 

 inch long) in around 35 days during warm weather. The mature 

 larva is grayish white and covered thinly with fine brown hairs. 

 When growth is complete, the larva transforms into the inactive pupal 

 stage and emerges a fully developed beetle in about 7 days in summer 

 and in 14 to 18 days in the cooler weather of spring and fall. The 

 four stages in the life cycle of the cigarette beetle are shown in figure 2. 



SEASONAL OCCURRENCE 



A wide variation in seasonal occurrence is exhibited by the cigarette 

 beetle because of the variety of conditions under which tobacco and 

 its products are handled, and because of the diverse climatic conditions 

 of the localities in which the beetle is commonly found. In heated 

 buildings or in the subtropical climate of southern Florida there may 



Figure 2. 



Stages of the cigarette beetle : A, Egg ; B, full-grown larva ; C, pupa ; 

 adult. Eleven times natural size. 



tnd D, 



be no well-defined hibernation period but a mere slowing up of de- 

 velopment in the egg, larval, and pupal stages during the cooler periods 

 of the year. Under these conditions each of the stages of the insect 

 may be found at almost any time during the year. In North Carolina, 

 Tennessee, and States farther north the beetle passes the winter in un- 

 healed buildings in the larval stage in tobacco or other foods. The 

 low temperatures prevailing in severe winters in these States may 

 materially reduce the population of overwintering larvae, especially 

 those that are younger and less mature. 



In Virginia and North Carolina the full-grown overwintered larvae, 

 or grubs, start pupation in April and the spring brood of adult beetles 

 begins to emerge in tobacco warehouses about May 15. There is con- 

 siderable overlapping of the generations, but there occur rather sharply 

 defined peaks of emergence of the broods of adults, which can be gaged 

 by suction light traps. The peak of emergence (presence of the largest 

 numbers) of the spring brood from 1933 to 1936 occurred in Rich- 

 mond, Va., during the weeks ending as follows: 1933, June 23; 1934, 

 June 29; 1935, July 5; and 1936, June 19. 



