8 FARMERS BULLETIN 846. 



tinuously in their food substance aid in their spread without much 

 effort on their part. 



The increase and spread of the insect in tobacco factories in this 

 country within comparatively recent years has been very noticeable. 

 Experienced tobacco dealers and manufacturers attribute this to the 

 more general use of steam for heating factories and other buildings. 

 The higher and more uniform temperatures maintained make breed- 

 ing conditions more favorable for the insect, and the chance that 

 development will be checked or the insects killed out by the cold 

 weather is not as great as before steam heat was employed. 



The recent rapid expansion of the tobacco industry has carried the 

 pest, in leaf tobacco or in tcbacco products, to many localities where 

 until within the last few years it had been imknown. 



In this country the beetle now is disseminated so generally that 

 it is a common occurrence to find it in show cases and storage rooms 

 or humidors in cigar stores where worthless or infested stock is not 

 properly treated or destroyed. The majority of shipments returned 

 to cigar and tobacco factories come from dealers in the South and 

 from other localities where climatic conditions are especially favor- 

 able for the rapid increase of the insect. Even in summer compara- 

 tively few complaints come from dealers in certain of the Northern 

 States and Canada. In view of these facts, when damaged goods are 

 returned to the manufacturers after having been in the hands of the 

 dealers for some time, it is always possible that the product was not 

 infested when shipped out from the factory. 



FOOD SUBSTANCES. 



The tobacco beetle feeds upon a variety of dried vegetable sub- 

 stances and upon a few of animal origin. Its more common food is 

 cured leaf and manufactured tobacco. In drug stores and grocery 

 stores often it is found infesting dried roots and leaves of certain 

 kinds and pressed yeast cake. In drug stores frequently it becomes 

 a serious pest and causes considerable loss. Numerous cases of in- 

 jury to plush upholstering in furniture and to dried plants in 

 botanical collections have been recorded. The insect also feeds upon 

 tobacco seed. 



LIFE HISTORY AND HABITS. 



Period of incuhation. — The e^g stage at ordinary temperatures in 

 summer lasts from (3 to 10 days. In Avarm Aveather during summer 

 it averages about 8 days. Eggs kept at a constant temperature of 



