10 



tion it was urged that this spray be adopted for the weeds on 

 ranch land. An extensive test was at once begun with results 

 which have justified the general application of arsenite of soda. 

 Not only the Hitchcock berry and German ivy are destroyed by 

 this spray but also the nettle (Hesperocnide sandwichensis) . 

 These are the very worst weeds on ranch land. The use of arse- 

 nite of soda as a spray seems to be a practical solution of the 

 problem of their eradication. Large bushes of Hitchcock berry 

 are destroyed by a single application. At any rate the roots 

 have been found to be dead for a distance of 18 inches from the 

 base of the trunk and, of course, the leaves and the stems were 

 all killed by the same treatment. 



The method of application of arsenite of soda on rough ranch 

 land or in rubber plantations is a simple one. The most of these 

 lands do not admit of horse-drawn spraying apparatus on account 

 of the junglelike nature of the weeds and the roughness of the 

 lands. A knapsack spray holding about 5 gallons of -solution 

 may be carried on the backs of laborers, who can readily make 

 their way through the bushes and grass, covering the vegetation 

 with the spray as they walk along. One laborer can spray from 

 one to two acres per day, depending upon the height and density 

 of the weeds to be sprayed and the character of the land. The 

 total cost of a single application, including materials and labor, 

 varies from $1.25 to $2.25 per acre. The flowers and tender 

 foliage of all weeds are destroyed by a single application and 

 this effectively prevents the immediate spread of the weeds. As 

 a rule the stems and roots of the weeds are destroyed by the 

 first application. Hilo grass, however, lantana and certain other 

 of the hardy weeds may require two or three applications for 

 their complete destruction. About 100 gallons of the diluted 

 spray is usually sufficient for an acre of ground. 



In spraying with arsenite of soda it should be remembered 

 that the effect is produced by contact with the aerial portions of 

 the plant. The spray should be applied in the form of a fine 

 mist so as merely to cover the surface of the leaves and the 

 stems. Care should be exercised not to drench the plants, since 



