9 



scale in Hawaii, the chief credit is due to Mr. W. A. Anderson, 

 Manager of the Xahiku Rubber Company. In consequence of 

 the satisfactory results which he has obtained, the method has 

 been generally adopted by all of the other rubber companies. 

 More than 500 acres of land covered with miscellaneous shrubby 

 and herbaceous weeds have already been cleaned by means of the 

 spray, and ultimately the whole area now planted to rubber will 

 be treated in this way. Some of the experience of Mr. Anderson 

 is stated as follows in a letter from him: 



"We use it for all troublesome grasses according to the following 

 formula: 2 pounds crystal sal soda, 1 pound arsenic, boiled in 1 gal. 

 water until clear. This is diluted in about 24 gals, of water in the 

 field and applied at the rate, roughly, of about 100 gals, of the diluted 

 mixture per acre, more or less according to the length and thickness of 

 the growth. 



"We find this effective for all the grasses we have to deal with, and 

 for the Hitchcock berry and for the general run of weeds, excepting 

 pualele (milkweed), ginger, and wild taro. For best results on hono- 

 hono a little stronger solution, perhaps one gallon of stock mixture to 

 20 of water, is necessary. Diluted 1 to 24, it is partially effective with 

 the three exceptions given above, and I feel sure that used slightly 

 stronger, it would dry them up, as it does the grasses and ordinary 

 weeds. 



"In a complete list of the plants affected, lantana could not be 

 omitted, as it burns the leaves off, and I have in mind a patch treated 

 over a year ago which has not grown yet. It is unquestionably safe 

 to say lantana can be kept in check with it, the fact having been dem- 

 onstrated that the growth above ground can be killed, the conclusion 

 would be natural that by keeping at it, the roots in time might be 

 starved out. 



"Hilo grass is actually disappearing from our fields that have been 

 plowed, and thereafter treated with the spray. Considerable areas are 

 entirely free from it, and it has been thinned out everywhere." 



For several years the Hitchcock berry or thimble berry, and 

 German ivy (Senecio mikanidides) have been encroaching on the 

 grass lands of some of the ranches on Hawaii, particularly the 

 Parker Ranch. The method of eradication at first adopted was 

 that of digging out by hand. In this way about $1500 per 

 month was being expended on these weeds and the financial bur- 

 den seemed an excessively heavy one for the single item of weed 

 eradication. As soon as the experiments with arsenite of soda 

 had been carried far enough to warrant a specific recommenda- 



