I will proceed now to discuss in detail the various control 

 measures suggested. 



1 . CLEAN " SETS " MUST BE PLANTED. 



The method of planting usually adopted in this country is to 

 plant lengths of cane about 18 inches (46 centimetres) long in pairs, 

 the pairs lying end to end and about 6 inches (15 centimetres) below 

 the level of the ground. At the present time it is practically impos- 

 sible to obtain cane for planting that does not carry living insects, 

 and every field planted is infected from the very start. If it is possible, 

 however, to so treat the " sets " before planting that all the insects 

 are killed without impairing germination then that cane will grow up 

 free from disease and any infection which appears subsequently will 

 have been derived from external sources. 



A series of experiments was carried out to find a solution for the 

 treatment of the " sets " which would not be too costly and yet meet 

 the requirements. A number of different liquids were tried and in 

 each case the " sets " were completely immersed. 



(a) Hot water at a temperature of 60C. only killed 10 per cent 

 of the insects and it failed to dissolve the wax or fibroid material. 



(b) Cyllin. Solutions of 3, 5, and 10 per cent were tried and the 

 mortality in each case was about 60 per cent. The wax appeared to 

 be partially dissolved, but the fibroid material was untouched. Cyllin 

 made up with hot water was also not fully effective. 



(c) Lysol. 3, 5, and 10 per cent gave the same results as in the 

 case of Cyllin. 



(d) Clensel gave the same results as Lysol and Cyllin. 



(e) Carbon Bisulphide. This was very effective. Immersions 

 for twenty seconds killed every insect, but it is unsatisfactory owing to 

 the fact that it is expensive and extremely inflammable. It would be 

 dangerous to handle in large quantities. 



(/) Paraffin emulsion. This gave excellent results. The stock 

 solution was tried at various dilutions and it was found that a dilution 

 of one in thirty killed every insect if the set was immersed for two 

 minutes. This solution dissolves the wax, has a good wetting power, 

 and kills 100 per cent of the insects. 



The proportions of the ingredients in the stock solution are as 

 follows : 



Paraffin or petroleum 2 gallons. 



Water 1 gallon. 



Sunlight soap 1 lb. 



