308 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Hawaii Station. 



The Hawaii station continued its policy of giving encouragement 

 to minor agricultural industries of the islands in the hope that a more 

 diversified agriculture will be developed. J. M. Westgate, formerly 

 of the Bureau of Plant Industry of this department, continued in 

 charge of the work at this station. 



One of the achievements of the station during the past year was the 

 discovery of an efficient means for the control of the yellowing of 

 pineapple plants on soils having a comparatively high content of 

 manganese. The yellowing of the leaves is followed by a poor devel- 

 opment of the fruit, which, by reason of its small size and acidity, is 

 worthless for canning. By the simple expedient of spraying the 

 plants several times with a solution of iron sulphate or iron chlorid, 

 the green color is restored to the leaves and the fruit develops in a 

 normal manner. This treatment was tested on a field scale and 20 

 tons of fruit per acre were secured at a cost of only $2.50 per acre. 

 Adjacent untreated plats were not considered worth harvesting. If 

 on further trial the preliminary results are confirmed, it is estimated 

 that from G,000 to 10,000 acres of land can be added to the pineapple- 

 producing area of the islands. In some portions of the islands it has 

 been found difficult if not impossible to sustain the large yields of 

 pineapples, and work is in progress to determine what rotations can 

 be adopted that will prove economically profitable. As a phase of 

 this work, several lines of pineapple breeding have been begun. 



In order to maintain fertility of the soil the station has been giv- 

 ing considerable attention to the growing of green manure crops. 

 Experiments with more than 20 species of leguminous plants have 

 been completed, and the chemical features of the experiment have 

 been written up for publication. A number of rapidly growing 

 species were found to be very efficient in maintaining the humus con- 

 tent of the soil, and at the same time restore the nitrogen required by 

 other crops. 



The work with forage crops was extended, and increase plats 

 w T ere established for a number of the more promising species. 

 This work is being extended throughout the islands through the 

 -collaborators of the stations and cooperating individuals. Consider- 

 able interest has been aroused in growing certain selected sorghums 

 for utilization as chicken feed. At present nearly all poultry feed 

 is imported from the mainland, and the local growing of feed is con- 

 sidered important in view of the recent interest manifested in the 

 poultry industry. 



In the horticultural department, in addition to the pineapple- 

 breeding work, similar breeding experiments are being carried on 

 with mangoes, avocados, and papayas to develop improved varieties 

 of these tropical fruits. Some investigations were begun with 

 the litchi, a Chinese fruit of remarkable character. Methods of 

 propagation are being sought which will be more certain than the 

 oriental methods of air la} 7 ering now commonly followed. A very 

 successful experiment in the shipment of litchi seed was carried 

 out between the station and Bureau of Plant Industry of this de- 

 partment. In connection with the study of the litchi a rather serious 

 disease, due to mites, was discovered, for which a satisfactory method 

 of treatment has been found. 



