2 CIRCULAR 462, U. S. DEPARTMENT OF AGRICULTURE 



Runner 2 found that all stages of the cigarette beetle could be 

 killed by exposure to temperatures of between 14° and 20° F. He 

 found that eggs in cigars could be killed by a 1-day exposure to 

 temperatures below 20°. Boxes of cigars infested by all stages of 

 the beetle were completely disinfested by a 7-day exposure at an 

 average temperature of 14°. All stages of the beetle were killed in 

 a bale of cigar tobacco in a 28-day exposure at the same temperature. 

 Powell 3 reports that only 57-percent mortality was obtained in eggs 

 held for 20 days at a temperature of approximately 35°. Neither 

 author endeavored to find the minimum exposure required to give 

 complete control at any given temperature. In the work recorded in 

 this circular an attempt was made to establish the minimum exposure 

 for complete control at temperatures of 10°, 15% 20°, 25°, 30°, 32°, 

 36 c . ancf 40°. 



OBTAINING STOCKS OF THE INSECT FOR THE EXPERIMENTS 



All the insects were reared at Richmond, Va., by the tobacco insect 

 laboratory of the Bureau of Entomology and Plant Quarantine 

 and brought by rail or automobile to Takoma Park, Md., or Arling- 

 ton, Va., where the tests were made. Although the insects can be 

 reared on several different diets, whole corn meal has been found 

 very satisfactory and is used almost exclusively at the Richmond 

 laboratory. The stock formerly was reared in Petri dishes, but these 

 have been displaced by pint fruit jars with tight muslin caps. The 

 jar is half filled with corn meal tamped down to insure a firm sur- 

 face on which the beetles can walk. Here the females lay their 

 eggs, and the resulting larvae feed downward into the corn meal. 

 The mature larvae pupate in the corn meal near the surface in small 

 cells which they make by cementing meal dust about themselves. 



The adults are collected from the top of the jar into a modified 

 Erlenmeyer flask connected to a vacuum pump. With this apparatus 

 the insects can easily be counted and picked up without injury. 

 Larvae were obtained by first screening them from the corn meal and 

 then collecting them in the vacuum flask. Pupae were collected in a 

 similar manner but were allowed to remain in their cells throughout 

 exposure and subsequent incubation. Removing them from the cells 

 was not practical because of the probability of injuring them when 

 breaking open the relatively hard shell. Eggs were obtained by con- 

 fining several hundred adults in a Petri dish with two short pieces 

 of tobacco stems, or midribs, about 1*4 inches long. The small white 

 eggs were deposited in cracks in the stems, and they were exposed 

 to the cold by placing these stems directly in the cold room without 

 disturbing or even counting the eggs. 



EFFECT OF LOW TEMPERATURES ON THE INSECT 

 METHODS USED IN THE EXPERIMENTS 



The tests to determine the lethal exposure period were made in 

 the cold-storage laboratory of the Bureau of Plant Industry, at 



2 RUNNER, G. A. THE TOBACCO BEETLE : AN IMPORTANT PEST IN TOBACCO PRODUCTS. 



U. S. Dept. Agr. Bull. 737, 77 pp., illus. 1919. 



3 Powell, T. E., jr. an ecological study of the tobacco beetle, lasioderma 



SERRICORNE FABR., WITH SPECIAL REFERENCE TO ITS LIFE HISTORY AND CONTROL. Ecol. 



Monog. 1 : 333-393, illus. 1931. 



