542 



leaves being divided, and in appearance like those of the vetch, pea, 

 mimosa cassia or crotalaria. 



As the chief cost of an estate until its profit-earning period is that 

 of weeding, any suggestion as to the reduction of that prime expense 

 should meet with consideration. 



If every estate would set apart a portion of their newly opened 

 clearings for an experiment with a green manure, keeping a record of 

 the cost of putting the land into Crotalaria, Mimosa, Desmodium and 

 whatever other useful plant is selected, and recording the money spent 

 on adjoining land cultivated on the existing clean-weeding method, and 

 carefully measuring the trees on each place to see the relative progress, 

 I have little doubt that the benefit of keeping the soil covered, instead 

 of constantly scraping off the weeds, will be seen. 



That the planter should adopt suggestions made by scientific 

 experts without weighing them carefully is not to be expected, but what 

 is wanted is that each practical man should satisfy himself by careful trial 

 that this proposal in regard to cultivation of rubber estates is feasible. 



Even if this experiment results in a loss of money and the des- 

 truction of a few acres of rubber he cannot be blamed in making it, 

 considering the large economy that is to be effected if it is proved to be 

 successful. 



Weed Killing by Spraying. 



The experiments in regard to the eradication of lalang and other weeds 

 by means of spraying with a solution, of arsenite of soda were carried on 

 both by the department and by several planters with encouraging success. 

 The difficulties in regard to the prohibitive cost which was charged 

 locally has been to some extent overcome, and supplies of this substance 

 were obtained from Calcutta at one-fifth of that charged in the Federated 

 Malay States. 



This cost is, however, too great, it can be obtained in England at a 

 cost, including freight to Port Swettenham, at about 12 cents per lb. 

 As the chief cost in this method of destroying weeds is the cost of the 

 material used in the spray it is most important to obtain the arsenite of 

 soda as cheaply as possible. The difficulty in regard to sprayers has 

 also been to a great extent overcome, and though it is not yet possible to 

 get suitable sprayers locally yet some English and American machines 

 at varying prices from $1 for hand sprayers to $250 for steam power 

 have been investigated and shown to be suitable to the purpose. 



While the use of arsenite of soda was first investigated as men- 

 tioned in my last report for the eradication of the most pestilent weed, 

 lalang {Imperata arundinacea) , this method of getting rid of weeds is 

 still more efficacious in the case of other weeds submitting a larger and 

 flatter surface to the spray. The leaves are all killed within 48 hours 

 and should be left to rot on the ground and not pulled out or scraped 

 away, by this means the soil is protected from rain and sun, and if the 

 plant becomes green it can be again sprayed. The cost of this method 

 of destroying weeds necessarily varies with the character of the fields 

 to be sprayed, but in the most cases with hand atomiser sprayers 

 the cost should not be 50 cents per acre where very weedy, and on 

 ordinary fields probably not more than 10-15 cents. 



