STATES RELATIONS SERVICE. 589 



The station continued its efforts for the control of cattle ticks 

 which started with the construction at the station of the first dip- 

 ping tank on the island. There are now nearly 200 public and 

 private dipping vats in the island and sentiment is believed to have 

 been developed that will result in an eradication campaign by the 

 insular authorities in the near future. Following the cleaning up 

 of individual plantations, the livestock industry, and especially 

 dairying, has received a great impetus and many purebred animals 

 are being introduced. The station showed the value of purebred 

 sires in the upgrading of its dairy herd, which now consists mostly 

 of three-quarters or seven eighths grade Guernseys. The milk pro- 

 duction of the grades largely exceeds that of a number of native 

 cows whose records were obtained. 



In the rapid development of the cattle industry that has taken 

 place during the last few years the activity of the station in the in- 

 troduction and dissemination of improved forage plants has played 

 an important part. Napier or elephant grass, Guatemala grass, and 

 velvet beans, all of which were introduced by the station, have 

 proved well adapted to local conditions, and many individual plant- 

 ers now have large acreages of each from which their neighbors can 

 obtain seed and cuttings for planting. Another important intro- 

 duction was Uba sugar cane, which is not affected by the mosaic 

 disease that is so destructive to many of the varieties commonly 

 grown. The first of this variety of cane grown in Porto Kico was 

 introduced by the station, and extensive trials have shown that in 

 addition to being resistant to the mottling disease, or mosaic, it 

 tillers well and produces a high tonnage of cane. On the higher 

 lands, where the standard varieties can not be grown at a profit, 

 Uba cane is giving excellent results. The station has continued its 

 activities in the production and testing of seedling varieties of sugar 

 cane, and during the current year about 15,000 seedlings were pro- 

 duced from which to make selections. New seedling varieties are 

 rapidly replacing the old ones which have deteriorated from various 

 causes. 



In 1909 the station began an experiment in growing vanilla in 

 Porto Rico, and it reports that one planter has now 10 acres of old 

 coffee land planted to vanilla. In 1922 he harvested from 2 acres 

 of vanilla, planted in 1918, and from scattered plantings just coming 

 into bearing, 850 pounds of cured beans for which he received $4 per 

 pound. Vanilla culture has been found quite profitable in connec- 

 tion with the renovation of coffee plantations, and a number of 

 planters are taking up this new industry. 



A very satisfactory experiment in the control of citrus scab waw 

 conducted during the year. More than 3,000 grapefruit trees were 

 sprayed four times with Bordeaux mixture to which 0.5 per cent 

 of oil emulsion was .added, with the result that the sprayed trees 

 produced fruit, 94.4 per cent of which was entirely free from scab as 

 compared with less than 10 per cent clean fruit from the unsprayed 



trees. 



Tobacco manufacturers in Porto Rico often experience heavy losses 

 due to the tobacco, or cigarette, beetle. So great was the damage 

 done by this pest that one of the largest manufacturers of cigars 

 enlisted the station in an investigation of the matter and financed 

 cooperative experiments in the fumigation of all its factories and 



