THE CHEESE SKIPPER AS A PEST IX CURED MEATS 



41 



In an ammonia refrigerating machine at 0, J, 10, and 15° F. — 

 Table 17 gives results of a few experiments in an ammonia refriger- 

 ating machine at temperatures considerably below freezing. The 

 larvae which were able to survive the cold for periods of 44 hours 

 or mere were less than half grown; all maggots of other sizes 

 were killed. It is interesting to note that these larvae survived low 

 temperatures for periods greatly in excess of the exposures which 

 killed all stages of a variety of other species of stored-product insects 

 which have been tested with the ammonia machines. 



Table 1' 



-Results of exposing adults, pupa\ and mixed- sizes of larva? of 

 Piophila* easel to low temperatures 



Stage 



0° F. 



5° F. 10° F. 



15 c F. 



Results 





Hrs. 



Hrs. Hrs. 



Hrs. 



All dead. 





mi 



16H 



W/ 2 



24 



24 



24 



16H 



16^ 



16H 



24 



24 



24 



41 





Xot all dead. 



Pupae . ..... .. . ... ... . J . 



Do. 



Adults.. . . ... ________ — — — _— 



All dead. 





Do. 







Adults 



All dead. 





Do. 



Do... 



41 



44 





Do 



44 





Do.i 



Do. . 



64J^ 





20sy 2 



Do. 1 









i Of mixed sizes of larvae subjected to these exposures, only specimens less than half grown survived. 



A large number of full-grown larvae were placed in an outdoor 

 fumigating box on December 16, 1922. On February 27, 1923, sev- 

 eral hundred were removed to room temperatures and all of them 

 became active after about 15 minutes, and subsequently developed 

 into adults which laid fertile eggs. 



EFFECT OF HIGH TEMPERATURES 



Except for the statement of Grinnan (29) that he was accustomed 

 to place infested meat in the sun to kill the skippers in it, and a record 

 by Alessandrini (4) that 55° C. (131° F.) was fatal in two minutes, 

 there is no published mention of the use of heat as a control measure. 

 At a small abattoir near Washington the resmoking of infested 

 meat was tried with some success several years ago, but as this 

 involves considerable labor in handling the meat, the writer at- 

 tempted to raise the temperature of the meat as it hung in the 

 storage room. The results were negative. After several hours the 

 kerosene heaters, as expected, so exhausted the oxygen of the com- 

 partment that they were extinguished, and sufficient ventilation to 

 allow them to burn freely kept the temperature from rapidly reach- 

 ing the required point. It is possible, however, that under certain 

 conditions steam heat may be used effectively. When the kerosene 

 stoves were used — and their use to produce high temperatures is not 

 safe — the reading of the thermometer at the floor, which was about 

 68° F. at the start was 98.5° after 15 hours of constantly rising 

 temperature; halfway up to the ceiling it was 115°, and at the ceil- 

 ing, 132°— a difference -of 33.5° between floor and ceiling in a room 

 7 feet 6 inches high. The floor was of concrete and the walls and 



