﻿212 
  W. 
  A. 
  LAM 
  BORN. 
  — 
  THE 
  AGRICULTURAL 
  PESTS 
  

  

  containing 
  8 
  oz. 
  of 
  sound 
  maize. 
  Oviposition 
  took 
  place 
  at 
  once 
  and 
  a 
  few 
  days 
  later 
  

   a 
  large 
  number 
  of 
  larvae 
  hatched 
  out. 
  At 
  the 
  end 
  of 
  two 
  months, 
  on 
  30th 
  December,, 
  

   two 
  generations 
  had 
  completed 
  their 
  life-cycle 
  ; 
  the 
  maize, 
  shaken 
  free 
  of 
  debris„ 
  

   had 
  lost 
  25 
  per 
  cent, 
  in 
  weight, 
  and 
  50 
  per 
  cent, 
  of 
  the 
  grain 
  showed 
  evidence 
  of 
  attack.. 
  

   For 
  the 
  purpose 
  of 
  freeing 
  the 
  seed 
  maize 
  at 
  Moor 
  Plantation 
  from 
  these 
  insect 
  pests^ 
  

   it 
  was 
  fumigated, 
  after 
  preliminary 
  experiments, 
  with 
  carbon 
  bisulphide, 
  employed 
  

   as 
  suggested 
  by 
  the 
  Imperial 
  Institute, 
  at 
  the 
  rate 
  of 
  5 
  lb. 
  per 
  1,000 
  cubic 
  feet 
  of 
  space, 
  

   and 
  fumigation 
  of 
  each 
  batch 
  was 
  made 
  to 
  extend 
  over 
  five 
  days, 
  by 
  which 
  time 
  it. 
  

   was 
  anticipated 
  that, 
  even 
  if 
  the 
  eggs 
  of 
  the 
  pest 
  had 
  not 
  been 
  killed, 
  the 
  larvae 
  would 
  

   have 
  hatched 
  out 
  and 
  perished. 
  

  

  These 
  anticipations 
  seemed 
  at 
  first 
  to 
  be 
  fully 
  realized 
  and 
  for 
  some 
  time 
  there 
  were 
  

   no 
  signs 
  of 
  living 
  pests. 
  But 
  at 
  the 
  end 
  of 
  about 
  three 
  months, 
  greatly 
  to 
  my 
  surprise 
  

   and 
  disappointment, 
  weevils 
  and 
  grain 
  beetles 
  reappeared 
  in 
  some 
  of 
  the 
  sacks. 
  I 
  

   then 
  made 
  a 
  careful 
  examination 
  of 
  the 
  fumigating 
  bins, 
  and 
  discovered 
  defects 
  both 
  

   of 
  construction 
  and 
  of 
  material 
  by 
  which 
  the 
  success 
  of 
  the 
  fumigation 
  might 
  have 
  

   been 
  vitiated. 
  Moreover, 
  on 
  turning 
  my 
  attention 
  to 
  the 
  store 
  itself, 
  I 
  found 
  

   numerous 
  slits 
  in 
  the 
  boarding 
  of 
  the 
  roof, 
  by 
  which 
  any 
  number 
  of 
  insect 
  pests. 
  

   might 
  subsequently 
  have 
  entered. 
  As 
  a 
  result, 
  the 
  pests 
  increased 
  to 
  such 
  an 
  extent 
  

   that 
  further 
  fumigation 
  was 
  urgently 
  called 
  for. 
  Unfortunately 
  the 
  double 
  fumi- 
  

   gation 
  affected 
  the 
  germinating 
  powers 
  of 
  most 
  of 
  the 
  seed, 
  but 
  I 
  am 
  confident 
  that 
  

   if 
  the 
  operation 
  could 
  be 
  carried 
  out 
  under 
  favourable 
  conditions 
  in 
  properly 
  con- 
  

   structed 
  receptacles, 
  and 
  if 
  the 
  grain 
  were 
  kept 
  subsequently 
  in 
  a 
  well-made 
  store, 
  

   adequately 
  ventilated, 
  a 
  single 
  fumigation 
  of 
  the 
  strength 
  recommended 
  would 
  suffice 
  

   to 
  exterminate 
  entirely 
  all 
  forms 
  of 
  the 
  pests. 
  

  

  At 
  the 
  suggestion 
  of 
  Mr. 
  A. 
  H. 
  Kirby, 
  the 
  Assistant 
  Director 
  of 
  Agriculture, 
  and 
  in 
  

   collaboration 
  with 
  him, 
  experiments 
  were 
  made 
  as 
  to 
  the 
  value 
  of 
  the 
  fumigation 
  of 
  

   grain 
  against 
  insect 
  pests 
  with 
  carbon 
  dioxide. 
  In 
  default 
  of 
  more 
  suitable 
  apparatus, 
  

   kerosene 
  tins 
  were 
  filled 
  with 
  infested 
  grain 
  and 
  carbon 
  dioxide 
  was 
  driven 
  in, 
  the 
  

   tins 
  being 
  then 
  sealed. 
  At 
  the 
  end 
  of 
  ten 
  days 
  the 
  tins 
  were 
  ventilated 
  and 
  again 
  

   sealed. 
  The 
  results 
  were 
  entirely 
  satisfactory, 
  no 
  living 
  pests 
  being 
  found 
  months 
  

   later, 
  and 
  the 
  germination 
  percentage 
  being 
  very 
  high. 
  I 
  wish 
  to 
  take 
  this 
  opportunity 
  

   of 
  thanking 
  Mr. 
  Kirby 
  for 
  his 
  very 
  valuable 
  suggestion. 
  

  

  When 
  tried 
  on 
  a 
  larger 
  scale 
  in 
  one 
  of 
  the 
  bins 
  the 
  results 
  were 
  not 
  so 
  good, 
  but 
  I 
  

   subsequently 
  found 
  a 
  large 
  crack 
  in 
  the 
  floor 
  by 
  which 
  the 
  gas 
  doubtless 
  leaked 
  out 
  

   prematurely. 
  

  

  Insect 
  Pests 
  of 
  Rubber. 
  

  

  Para 
  rubber 
  pianos 
  were 
  singularly 
  free 
  from 
  insect 
  attack, 
  the 
  only 
  leaf-eater 
  

   found 
  being 
  the 
  omnivorous 
  grasshopper, 
  Zonocerus 
  variegatus, 
  which 
  attacked 
  young 
  

   nursery 
  plants, 
  those 
  that 
  were 
  not 
  well 
  shaded 
  being 
  far 
  more 
  damaged 
  by 
  these 
  

   sun-loving 
  pests 
  than 
  those 
  which 
  were 
  more 
  sheltered. 
  

  

  The 
  large 
  cricket, 
  Brachytrypes 
  membranaceus, 
  Drury, 
  which 
  sometimes 
  fed 
  on 
  

   the 
  roots 
  of 
  young 
  plants, 
  was 
  responsible 
  for 
  a 
  slight 
  loss, 
  but 
  it 
  was 
  preyed 
  on 
  by 
  

   the 
  fossorial 
  wasp, 
  Chlorion 
  xanthoceros, 
  Illig., 
  var. 
  instabilis, 
  Sm., 
  which 
  thus 
  acts 
  

   as 
  a 
  valuable 
  natural 
  check. 
  

  

  Funtumia 
  elastica 
  is 
  attacked 
  by 
  two 
  Lepidopterous 
  leaf-eaters, 
  the 
  larva 
  of 
  a 
  

   species 
  of 
  Sphingid 
  moth.of 
  the 
  genus 
  Nephele, 
  which 
  is 
  much 
  parasitised 
  by 
  Braconids,, 
  

  

  