THE SUGAR-CANE MOTH BORER. 



51 



Table VIII. — Effect on moth-borer larvw of immersion of infested, cane 

 cuttings — Continued. 



Solution. 



Expo- 

 " sure. 



Num- 

 ber of 

 lar- 

 vae. 



Condition of larvae im- 

 mediately after treat- 

 ment. 



Penetration of solution 

 in cane cutting. 



Condition 

 of larvse 

 two weeks 

 after treat- 

 ment. 



Nicotine sulphate (40 per 

 cent nicotine), 1 part 

 to 500 parts water. 



Dip... 



lhour. 

 Dip... 



lhour. 

 ...do.. 



10 



7 

 7 



10 

 10 



9 alive, 1 small one dead 

 between stalk and leaf 

 sheath. 



Probably penetrated the 

 stalks. 



do 



4 alive. 



Potassium sulphid, 3 

 pounds per gallon 

 water. 





do 





.. do 



do 





Potassium sulphid 1$ 

 pounds per 10 gallons 

 water. 



All alive, 1 emerged from 

 cane and in the solu- 

 tion. 



do 









Soaking the cuttings for 1 hour in either Bordeaux mixture or 

 nicotine sulphate solution was found to kill all the larvse within 2 

 weeks. Only 1 larva was killed immediately, however, even after 

 an immersion of 1 hour. 



Eggs, larvse, and pupae were next subjected to immersions of 1 

 minute and 1 hour in the various solutions, with results as shown 

 in Table IX. The larvae and pupae had previously been removed 

 from the stalks of cane. A cluster of eggs, 5 larvae, or 5 pupae 

 were used in each exposure. 



Table IX. — Immersion of eggs, larvw, and pupce of the moth borer in various 



solutions. 



Solution used and stage of insect. 



Exposure. 



Effect within 2 

 days. 



Effect within 10 

 days. 



T jdeaux mixture: 



Eggs 





Did not kill 



do 



All hatched. 









Do : 





do 







do 



do 





Pish-oil soap: 



Eggs 



do 



do 









do 





Do 





do 





Pups 



do 



.All killed 





Nicotine sulphate (40 per cent nicotine): 



Eggs 



.. ..do 



None hatched 



Didnot kill 



do 





Larvse 



1 minute 





Do 



Do. 



Pupae 



do 



do 





Potassium sulphid, 3-100: 



Eggs 



do 



do 









.. . do 





Do 





do 







do 



do 



All emerged. 



Potassium sulphid, 1J-100: 



Eggs 



do 



do 



Larvae 



1 minute 



...do 





Do 



do 



All healthy. 



Pupae 



do 



do 













Untreated eggs used as a check hatched as usual. Of 5 untreated 

 larvae, 1 died within 10 days. All of the 5 untreated pupae were 

 alive at the end of 10 days. 



It will be noted that pupse immersed for one hour in fish-oil soap 

 solution were killed, while eggs immersed for one hour in nicotine- 

 sulphate solution did not hatch. The other solutions were ineffective. 

 It is evident that larvae and pupae are more seriously affected by these 



