PINK BOLLWORM OF COTTON IN MEXICO. 



49 



tailed account of the fumigations that were made with carbon 

 disulphid. 



Table XXV. — Preliminary fumigation experiments with carbon disulphid for P. gos~ 



sypiella in cotton seed. 





Dosage. 





Experi- 

 ment 

 No. 





Length 

 of ex- 

 posure. 



Pounds. 



Cubic 

 feet. 









Hours. 



1 





102 



90 



2 





161 



48 



3 





289 



48 



4 





161 



23 



5 





161 



23 



6 





161 



48 



7 





103 



48 



8 





124 



48 



9 





82 



48 



>10 





54 



24 



11 





80 



42 



13 





100 



1 week . 



19 





100 



Hours. 



48 



20 





80 



48 



21 





80 



48 



22 





80 



48 



23 





80 



24 



26 





80 



12 



27 





80 



15 



29 





85 



24 



30 





85 



24 



31 

 32 





90 

 90 



24 

 24 



How seed was 

 stored. 



In sacks. 

 ....do... 

 ....do... 

 ....do... 

 ....do... 

 In bulk . 

 ....do... 

 ....do... 

 ....do... 

 ....do... 



In bags. 



In bulk 6 feet deep 



In bulk 5 feet deep . 



....do 



....do 



.do. 

 .do. 

 .do. 



.do. 



.do. 



.do. 



.do. 

 .do. 



Location of larvae. 



/Top sack 



(Bottom sack 



(Top sack 



(Bottom sack 



/Top sack 



(Bottom sack 



(Top sack 



\Bottom sack 



/Top sack 



\Bottom sack 



f 2-J feet deep '. . 



\4| feet deep 



(21feet deep 



\4ffeet deep 



/21feet deep 



\4§feet deep 



/21 feet deep 



\4|feet deep 



Mfeet deep 



l4j feet deep 



(On top 



< In center 



|On bottom 



I On top 

 2 feet deep 

 4 feet deep 

 6 feet deep 



{18 inches from top. 

 Middle 

 Bottom 



/Middle 



IBottom 



/Middle 



IBottom 



(Middle 



IBottom 



Bottom 



(Middle 



\Bottom 



(Middle 



(Bottom 



(Middle 



(Bottom 



(Middle 



\Bottom 



Bottom 



do 



Total 



per 



cent 



killed. 



94 



iln Experiment No. 10 the larvae were placed in glass tubes, which were closed with cork stoppers, 

 making them approximately air tight. 



In experiments 20, 21, and 22 all larvse were killed with 1 pound 

 of disulphid to 80 cubic feet in 48 hours. In order to shorten the 

 time, experiments 23, 26, and 27 were made, and all the larvse were 

 not killed. All of the disulphid had not evaporated at the end of 

 12 and 15 hours in experiments 26 and 27, but it had evaporated in 

 experiment 23 in 24 hours, and all the larvse were killed, showing 

 that 24 hours are necessary to evaporate and to secure maximum 

 penetration of 1 pound of disulphid in 80 cubic feet. This was in 



