748 EXPEEIMENT STATION RECORD. 



erosion. The trees protect each other against wind damage and tapping re- 

 turns for the fii-st few years are greater. 



The cheapest effective method of weed eradication is by means of arsenite 

 of soda, but this substance should not be allowed to touch the folinge of any 

 trees, or the stems of Oeara trees under 2 years of age or older trees where the 

 outer bark has been recently removed. Arsenite of soda should never touch 

 Hevea trees. Indications are that soil aeration in the Nahiku rubber district 

 can be obtained without excessive erosion by using dynamite. The results from 

 the fertilizer tests thus far made seem to indicate that the additional cost of the 

 fertilizers does not warrant their use. 



The best method of tapping so far discovered is by removing the outer bark 

 in narrow vertical strips and tapping these strips by incision, allowing the 

 latex to coagulate on the ground. The method of tapping is described in detail. 

 Relative to the proper season for tapping, it is concluded that good yields can 

 be obtained from September to April in ordinary seasons. 



Although a large amount of dirt is collected with the rubber allowed to flow 

 on the ground, this is removed by washing with corrugated rollers which leave 

 it in the form of coarse crepe. A uniform product of high quality is obtained 

 by drying for 2 weeks or more in the air at ordinary temperature and finishing 

 in a vacuum dryer at a temperature not greater than 120° F. 



The product of the Hawaiian plantations can be depended upon to bring a 

 price within from 5 to 10 per cent of that of Ceylon plantation rubber. 



The effect of nitrate of soda and saltpeter on the flow of Ceara latex, R. D. 

 ANSTEAD {Planters' Chron., 8 {1013), No. 32, pp. 38^-387).— In continuation of 

 the i)revious preliminary experiment (E. S. R., 25, p. 240) trials were made 

 during 1912 with both nitrate of soda and nitrate of potash on plats of 50 

 trees each. 



The results of the tapping experiments as here tabulated and discussed again 

 show that nitrate of soda does stimulate the flow of latex on areas which have 

 not normally yielded well. On other areas it apparently does not improve the 

 condition. Nitrate of potash appears to give a still greater latex yield than 

 nitrate of soda on areas which do not normally yield well. The experiment is 

 to be continued. 



Castilla rubber in Dominica, .7. Jones and G. A. Jones {West Indian Bui., 

 13 {1913), No. 3, pp. 253-258). — A review of various tapping experiments that 

 have been made with Castilla rubber trees leads the authors to conclude that 

 as far as conditions in Dominica are concerned the yields do not warrant the 

 cultivation of Castilla elastica. 



DISEASES OF PLANTS. 



Report of tlie department of botany, O. Bittler {Ncid Hampshire Sta. Bnl. 

 163, m). 16, 17). — A brief account is given of the botanical work in progress at 

 the station, two of the investigations having been reported upon elsewhere 

 (E. S. R., 27, p. 849; 28, p. 348). Notes are also given on the leaf spot of the 

 apple due to Sphwropsis malorum. 



Work connected with insect and fungus pests and their control, F. Watts 

 {Imp. Dept. Agr. West Indies, Rpt. Bat. Sta. Montserrat, 1911-12 pp. 16, 17).— 

 Experiments with 5 varieties of peanuts were carried out in 1911 in which 

 applications of Bordeaux mixture were made 77 and 102 days after planting. 

 It is admitted that as the results are inconsistent it has not been demonstrated 

 that the fungus was in the past years responsible for a shortened crop or that 

 it affected the quality of the nuts in any way. 



