and Magazine of the Ceylon Agricultural Society.— August, 1912. 



183 



give promise of being good covers, but the first 

 year's results with leguminouscrops are usually 

 uncertain. 



Lack or Cultivation. 

 The cultivation usually given to rubber trees 

 is hardly worth the name, consisting, in the 

 majority of cases, of a scraping the surface of the 

 soil to remove the weeds. I am of opinion that 

 more than this is required to induce and main- 

 tain healthy soil conditions. At least once a 

 year, probably twice would be better, the soil 

 should receive a thorough cultivation to a depth 

 of at least four inches. This would break up 

 the hard surface layer and allow the free access 

 of air to the soil in which the roots are feeding, 

 and would thus tend to create a healthier condi- 

 tion for root growth and for the continued pro- 

 duction of available food salts in the soil, I he 

 roots would not tend to grow in the surface layer 

 but would be forced deeper into the soil. During 

 dry weather the trees would not suffer to any- 

 thing like the same extent they do now, as the 

 soil water would be prevented from rising to the 

 surface when it evaporates. Combined with a 

 good leguminous cover crop, such a system of 

 cultivation, carried out from the beginning, 

 would, I am convinced, improve the growth and 

 health of the rubber immensely. 



The tapping of rubber trees is, 1 think, show- 

 ing improvement generally, both as regards 

 quality and quantity of bark removed. As regards 

 quantity of bark removed a conservative proce- 

 dure is more and more coming into favour and 

 very few estates now allow for less than four 

 years' renewal of the bark. The systems by which 

 this is brought about vary considerably, single 

 V s, one quarter half-herring bone, alternate 

 quarters, everyday and alternate day tapping, 

 all find their advocates, and probably the exact 

 system followed is not of primary importance. 

 Experiments are being carried out by the de- 

 partment on this point and will be referred to 

 later : unfortunately, reliable results cannot be 

 expected from these for at least four years, and 

 probably it will be safer^ to wait eight before 

 finally drawing conclusions from them. Some 

 estates are adopting systems allowing for even 

 more than four years' renewal of bark, while I 

 still find a few that are removing one-half their 

 tapping area each year; the condition of these 

 trees after the second round of tapping must 

 certainly be very poor. 



Space to quote more failing us, the following 

 points dealt with in the report may bo indicated : 



Extra work is thrown on estates by the demand 

 forlfghtcrepe,whioh is no better than any other. 



The rubber on many estates should be dried 

 more rapidly. 



White ants as pests are decreasing in number. 



A minute beetle has been reported from 

 time to time attacking rubber. 



Pollarding and pruning often give access to 

 pests. Wounds should be trdated with tar. So 

 should bad tapping. 



New rubber clearings have been affected by 

 a beetle that often kills 90 per cent of the 

 young plants. The remedy is a cylinder of 

 newspaper round the plant. 



Fomes still constitutes the most important 

 disease of the plant. Brown root disease oc- 

 curs only in small quantity. 



Diplodia (die-back) has been met with com- 

 monly in the year. Another fungus causes 

 death to tho tips of young shoots and gives a 

 foothold to diplodia. 



Two leaf diseases are reported, but the damage 

 done is small. 



Bark troubles require careful investigation 

 and this is to be given duriug the coming year. 



ERI SILK IN ASSAM. 



Mr. H. Maxwell Lefroy, Imperial Entomolo- 

 gist, and his Assistant, Mr. C. C. Ghosh, have 

 written an exhaustive account of the Eri silk 

 which is grown in Assam, and it has just been 

 published in the Entomological Series of the 

 Memoirs of the Department of Agriculture in 

 India, priced H3. The silk differs from other 

 silks in that it cannot be reeled, i.e., a siugle 

 continuous thread cannot be obtained from one 

 cocoon as is done in mulberry silk. The cocoon 

 actually is not formed of a long coutinuous 

 thread as in mulberry silk but is spun by 

 the worm in layers. It differs also from 

 these silk cocoons in that it is so made that 

 the moth can push its way through one end 

 without softening or cutting the fibres, this 

 end not being really closed but being so 

 blocked with loops of silk that nothing can 

 get in but the moth, pushing from within, 

 can force its way out. The silk has also this 

 peculiarity, that to gtt it the cocoons need not 

 be steamed to kill the insect within, as must 

 be done with mulberry or tussore silk ; the moth 

 may be allowed to mature inside theoocoon aud 

 emerge. This removes one of the objections 

 to mulberry silk, in that no life need be taken 

 before the silk can be obtained. The Memoir 

 is exoelloutly got up and well illustrated.— M. 

 Matt, June 8. 



