INJURIOUS INSECTS OF 1904. 



31 



PUP^. 



Effect of 

 exposure to 

 fumes of 

 Carbon 

 bisulphide. 



Effect of Low 

 Temperature. 



MOTHS. 



Effect of 

 exposure to 

 fumes of 

 Carbon 

 bisulphide. 



Effect of Low 

 Temperature. 



*24 hours' exposure to (1-5000) killed pupae. 



6^ days' exposure to 3 to 5 degrees above zero killed pupae.' 

 6^ days' exposure to 12 degrees above zero killed pupae. 



*24 hours' exposure to (1-5000) killed moths. 

 6 hours' exposure to (1-5000) killed moths. 

 42 hours' exposure to (i-ioooo) killed moths. 



6^ days' exposure to 3 to 5 degrees above zero killed moths. 

 6>4 days' exposure to 12 degrees above zero killed moths. 



CONCLUSIONS AND SUGGESTIONS. 



From the result of these experiments, the following conclusions 

 are drawn : 



Spraying eggs, larvae, pupae and moths with liquid CS2 is 

 fatal. 



Attempting to kill eggs by exposure to fumes of CS- is appar- 

 ently not practical. Hence when fimiigation of a mill is resorted 

 to (unaccompanied by spraying) the process should be repeated 

 ten days or later after first fumigation in order to kill the larvae 

 hatching from eggs which went safely throtigh the first fumigation. 



Fvill grown larvae and moths (and probably pupae) can be 

 killed by exposure for 42 hours to fumes of CS^ (i part liquid 

 CS2 to loooo parts of atmosphere). 



Larvae, pupae and moths in the center of tightly baled sacks 

 can be killed by 24 hours' exposure of fumes of bisulphide of car- 

 bon (i part liquid CS2 to 5000 parts of atmosphere). Forty-eight 

 hours' exposure where possible would be the preference of the 

 writer. Fumigation is, therefore, practicable treatment for infested 

 sacks in bale. 



*In this experiment, eggs, larv?e, pupje and motlis were enclosed in the very center of 

 a tightly packed bale of flour sacks before being placed in fumigation box, simulating as 

 nearly as possible the conditions which would exist in fumigating sacks in bale. As noted, 

 this kills moths, pups and larvae, but not the eggs. 



