CANE SUGAR. 



hours, and that there systematic collection over three years resulted in the 

 almost complete disappearance of the pest. Similarly, S. M. Hadi 13 states that 

 the white ant is in India attracted by dung which is purposely placed on the 

 cane fields as a means towards the collection and subsequent destruction of the 

 insects. 



3. Rotation of Crops. This has been recommended by Watson 7 as likely 

 to diminish the prevalence of the West Indian Root Borer (Diaprepes 

 abbreviatus), and amongst crops not attacked he mentions ochra, cassava, yams, 

 eddoes, woolley pyrrol, pigeon pea, bonavist and rouncival beans. 



4. Use of Substances objectionable to Insects. Wray states that cane tops 

 soaked for a few minutes in water tainted with petroleum are not attacked by 

 ants, and S. M. Hadi 13 mentions the use of mustard cake and assafcetida by the 

 ryots of India for a similar purpose. Naphthalene 9 has been used similarly to 

 impregnate the ground to repel the mole cricket in Porto Rico. 



5. Use of Insecticide Washes. Spraying as a means of the destruction of 

 insects is only effective with small crops grown on a restricted area, and has 

 but a limited use with the sugar cane. It has been employed chiefly in 

 connection with hemipterous pests, such as the Aphis and Mealy Bugs. leery, 

 in Mauritius, employed a wash formed by boiling lime and sulphur as a means of 

 destroying the pou-a-poche-blanche ; the most generally employed insect wash 

 is a petroleum emulsion made according to the following formula : 



1 part soap, 10 parts water, 20 parts petroleum ; the soap is dissolved in 

 hot water and the petroleum slowly added to the hot solution with constant 

 stirring. A creamy mass results, which for use is mixed with 15 parts of cold 

 water. On the small scale this solution is distributed from a knapsack spray 

 with a hand pump ; power sprayers conveyed in carts are also in use, but the 

 writer believes their employment is confined to the fruit industry carried on 

 over comparatively limited areas. 



Extract of pyre thrum is a widely used insecticide, and is thus prepared 14 : 

 Genuine Persian or Dalmatian insect powder, 100 grms. ; raw spirit, 

 200-250 grms.; 80-100 grms. ammonia; allow to stand for two days. 

 Dilute with two litres of water and allow to stand exposed to the sun for a 

 few more days ; filter through a cloth, squeezing out the residuum well. The 

 dark brown liquor is extract of pyrethrum. Use 25 grms. of this and 

 25 grms. of soft soap per litre in aqueous solution. 



6. Flooding. The flooding of fields has been proposed as a means of 

 destroying the larvae of those insects that are subterraneous in their habits. 



7. Destruction of breeding Places. Many of the parasites of the cane 

 utilize trash, dead cane, &c., as breeding -places, and following this the 

 destruction of all refuse likely to harbour insects has been advised ; agri- 

 culturally this process leads to a loss of nitrogen, and Perkins has observed 

 that the burning of trash, &c., may at times be ill-advised, as the leaf hopper 

 is able to escape by flight, a faculty not possessed by all its parasites. 



134 



