14 



CIRCULAR 269, U. S. DEPT. OF AGRICULTURE 



THE WORK OF LARVAE IN TOBACCO 



As the work of the larvae of the cigarette beetle (Lasioderma serri- 

 corne) is well known to the tobacco trade, the feeding of the larvae 

 of Ephestia elutella w^ill be contrasted w T ith that of larvae of the ciga- 

 rette beetle. The feeding of larvae of E. elutella is illustrated in 

 Figure 1 and that of cigarette-beetle larvae in Figure 6. 



Full-grown larvae or grubs of the cigarette beetle (fig. 7) are about 

 one-sixth inch long. They are yellowish in color and are usually 

 found lying in a curved position in their feeding tunnels. The bodies 

 are covered with brownish hairs, to which finely pulverized particles 

 of tobacco adhere. They tunnel through tobacco leaves in infested 

 hogsheads and cases, leaving holes that vary in size according to the 

 age of the larvae. 



The full-grown larvae of Ephestia elutella (fig. 2) are from three- 

 eighths to five-eighths inch long They are cylindrical, slightly tapering 



toward the head, and usually 

 of a brownish color when feed- 

 ing on tobacco. They have 

 brown spots on the dorsal side 

 of the body, which give them 

 a striated appearance, and the 

 bodies are sparsely covered 

 with colorless hairs. 



Larvae of E. elutella usually 

 feed from the stem end of 

 tobacco leaves toward the tip. 

 Figure 1 shows that a large 

 portion of the leaf surface is 

 consumed by these larvae. 

 They feed between the mid- 

 ribs and larger veins of the 

 leaves and pollute the uneaten 

 parts with webbing to which 

 particles of their excrement adhere. This webbing, with the at- 

 tached black pellets of excrement, is objectionable to buyers or manu- 

 facturers. Larvae have been found feeding as deep as 8 inches from 

 the staves of tobacco hogsheads, and have demonstrated their capacity 

 to damage stored leaf tobacco seriously. 



Larvae of the cigarette beetle eat or burrow irregularly shaped tun- 

 nels in the leaves. (Fig. 6.) Often these tunnels are filled with 

 tobacco dust and excrement of the larvae, which soils tobacco when 

 the infestations are heavy. 



THE PROBLEM OF CONTROL 



Tobacco is usually held in storage from one to three years for aging 

 before it is manufactured, and bright tobacco is sometimes held four 

 years or longer. It is therefore necessary for dealers and manufac- 

 turers to carry on hand from year to year large stocks of tobaccos. 

 Such long storage periods enable Ephestia elutella, under favorable 

 conditions, to build up large populations and inflict serious injury. 

 Examinations of infested hogsheads indicate that the pollution from 

 the webbing and excrement of the larvae often occasions greater losses 

 than the actual devouring of the leaf. The tobacco trade should make 

 a determined effort to locate warehouse infestations of this insect and 

 prevent their spread. 



Figure 7. — Larva, or grub, of the cigarette beetle 

 (Lasioderma serricorne) . A full-grown larva is about 

 one-sixth inch long when straightened out. (Back 

 and Cotton) 



