OFFICE OF EXPERIMENT STATIONS. 753 



a considerable number of trees of the better varieties. Experiments 

 are also in progress in improving the papaya, and it has been found 

 that by the use of the pistilhite phnits in an orchard the nonbearing 

 jstaminate plants can be eliminated. Enough perfect flowers are 

 produced for the purpose of fertilization and the seedlings from such 

 fruits are either all pistillate or perfect, and the results of crossing 

 are eliminated. Marked differences in quality, shipping, etc., have 

 been noted and the experiments are being conducted to improve these 

 characters. 



The entomologist has continued his studies of insect pests of agri- 

 cultural crops with a view to their control. Especial attention has 

 been given the insects attacking sweet potatoes in Hawaii, and a 

 bulletin prepared on the subject. Attempts are being made to intro- 

 duce parasites of the algaroba bean weevil, but the results thus far 

 can not be safely forecasted. Extensive additions were piade to the 

 collections of economic insects, and much work in breeding and life 

 history study is in progress. 



The' cooperative experiments on the rubber plantations have been 

 continued and the advantages of clean cultivation have been so evi- 

 dent that over 500 acres of planted rubber was given clean cultivation 

 this year. Spraying experiments were tried for the destruction of 

 weeds among the rubber trees, and it was found that the ground could 

 be cleared of all weeds by spraying w^ith arsenite of soda. About 

 400 acres were successfully cleaned in this way at a cost of about 

 $1.25 per acre. 



The station has taken up the problem of establishing demonstration 

 farms in different parts of the islands. The funds are supplied by 

 the territorial government, and it is proposed, as far as possible, to 

 work through the most successful farmer in the different homestead 

 communities. The work will be planned and directed by the station, 

 and the results can be interpreted by the man locally in charge. The 

 work for the present will be largel}' on better methods of cultivation, 

 rotation, and the introduction of new crops. 



PORTO RICO STATION. 



The new office and laboratory building provided from insular funds 

 was completed and occupied during the previous fiscal year, but 

 much of the work in connection with the installation of equipment 

 was not finished until 1910. The building has proved a model of 

 comfort and convenience. 



The relation of the station and its work to the people of Porto 

 Rico has grown closer with each succeeding year. This is evidenced 

 by the increasing number of visitors seeking information, the growth 

 of the corresponden'^e. and the numerous requests for assistance that 

 involve a personal visit of some member of the station staff. 



The work of the station during the past year has resulted in the 

 completion of some investigations that have been in progress for 

 several years and the extension of others. Although some of the 

 work of'the station has been conducted with a view to the immediate 

 results of practical importance, yet a strong and persistent effort is 

 being made so to shape the investigations as to determine some of 

 the fundamental principles underlying a rational system of tropical 

 agriculture. 



73477°— AG R 1910 48 



