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



regarded as an important natural control. The adult parasite (fig. 11) 

 is seldom found in large numbers until near the end of the summer, an 

 indication that it survives the winter conditions of storage in compara- 

 tively small numbers. The adults and pupae of this parasite over- 

 winter at or near the surfaces of hogsheads and bales of tobacco and 

 in cracks of walls or ceilings. Since these locations expose the insect 

 to the minimum temperatures reached in winter and also to fumigants 

 or other insecticides applied in the warehouses, this is an important 

 factor in reducing the number of parasites in tobacco storage houses. 

 Other natural enemies of the tobacco moth are mites of the genus 

 Laelaps, which prey on adults and eggs, and a spider, Theridion tepi- 

 dariorum Koch, which often constructs considerable webbing, in which 

 many moths are captured and destroyed. These mites and spiders 



Figure 11. — The braconid Microbracon hebetor, a larval parasite of the tobacco moth, 

 stinging a larvae of the Mediterranean flour moth (Ephestia huehniella) , a moth closely 

 related to the tobacco moth. Ten times natural size. (From Doten, Nev. Agr. Expt. 

 Sta. Tech. Bui. 78.) 



have not been observed in sufficient numbers, however, to indicate an 

 important degree of control. The hymenopterous parasite Mesostcnus 

 gracilis Cress, was collected in many localities in North Carolina and 

 Virginia and is especially abundant in farmers' pack houses. 



HOW INSECT INFESTATIONS ORIGINATE IN TOBACCO 



Domestic Flue-Cured Cigarette Tobacco 



When flue-cured tobacco is packed in hogsheads or cases after being 

 redried, it is free of all living insects. If. however, this tobacco is 

 allowed to remain for even a day or two in any building where tobacco 

 moths or cirgarette beetles are flying, it may become infested. The 



