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  PROCEEDINGS 
  OF 
  THE 
  FOUJITH 
  ENTOMOLOGICAL 
  MEETING 
  

  

  in 
  tte 
  grain 
  are 
  killed 
  and 
  in 
  bins 
  which 
  are 
  air-tight, 
  there 
  is 
  no 
  possibi- 
  

   lity 
  of 
  fresh 
  infection. 
  This 
  method, 
  if 
  found 
  successful, 
  will 
  be 
  the 
  

   simplest 
  and 
  the 
  best 
  for 
  grain 
  storage. 
  

  

  B. 
  In 
  the 
  second 
  category 
  we 
  include 
  all 
  those 
  processes 
  in 
  which 
  

   the 
  grain 
  is 
  first 
  subjected 
  to 
  treatments 
  which 
  make 
  it 
  free 
  from 
  all 
  

   stages 
  of 
  insects. 
  It 
  is 
  then 
  stored 
  in 
  insect-proof 
  stores. 
  In 
  cases 
  

   of 
  re-infestation 
  the 
  grain 
  has 
  to 
  be 
  treated 
  again 
  to 
  kill 
  the 
  pests. 
  The 
  

   methods 
  that 
  come 
  under 
  this 
  head 
  are 
  those 
  that 
  are 
  commonly 
  employed 
  

   at 
  the 
  present 
  time 
  and 
  particularly 
  where 
  large 
  quantities 
  of 
  grain 
  are 
  

   to 
  be 
  handled. 
  

  

  1. 
  Fumigation 
  : 
  — 
  ^Fumigation 
  is 
  a 
  process 
  which 
  is 
  very 
  commonly 
  

   resorted 
  to 
  for 
  freeing 
  grain 
  from 
  all 
  insects 
  attacking 
  it 
  and 
  also 
  to 
  kill 
  

   all 
  stages 
  of 
  insects 
  in 
  a 
  store 
  {6, 
  13), 
  The 
  gases 
  that 
  are 
  commonly 
  

   used 
  are 
  carbon 
  bisulphide, 
  hydrocyanic, 
  acid 
  gas 
  and 
  sulphur 
  dioxide. 
  

   Chlorpicrin, 
  which 
  is 
  said 
  to 
  give 
  good 
  results, 
  is 
  not 
  obtainable 
  here. 
  

  

  This 
  method 
  is 
  very 
  expensive 
  and 
  full 
  of 
  risks 
  under 
  Indian 
  con- 
  

   ditions 
  (1, 
  9). 
  The 
  two 
  g 
  ses 
  that 
  can 
  be 
  used 
  easily 
  are 
  carbon 
  bisul- 
  

   phide 
  and 
  hydrocyanic 
  acid 
  gas 
  ; 
  the 
  former 
  is 
  highly 
  explosive 
  and 
  

   latter 
  is 
  a 
  deadly 
  poison. 
  

  

  Moreover, 
  this 
  method 
  is 
  not 
  quite 
  reliable. 
  During 
  1920 
  we 
  tried 
  

   experiments 
  with 
  these 
  two 
  gases. 
  At 
  Hansi, 
  a 
  small 
  godown 
  was 
  

   fumigated 
  with 
  a 
  full 
  dose 
  of 
  hydrocyanic 
  acid 
  gas, 
  which 
  had 
  no 
  bad 
  

   effect 
  on 
  the 
  larvae 
  and 
  adults 
  of 
  Trogoderma 
  Ichapra. 
  We 
  only 
  succeeded 
  

   in 
  killing 
  a 
  number 
  of 
  mice. 
  Again 
  at 
  Hoshiaipur 
  we 
  tried 
  full 
  doses 
  

   of 
  carbon 
  bisulphide 
  and 
  hydrocyanic 
  acid 
  gas 
  to 
  fumigate 
  juar 
  seed 
  

   that 
  was 
  stored 
  in 
  a 
  room 
  in 
  the 
  mandi, 
  but 
  without 
  killing 
  the 
  insects. 
  

   Fletcher 
  also 
  mentions 
  this 
  method 
  as 
  unsuitable 
  for 
  India 
  (5). 
  

  

  2. 
  Mechanical 
  blowing 
  off 
  of 
  the 
  insects 
  : 
  — 
  In 
  the 
  elevator 
  at 
  Lyall- 
  

   pur 
  as 
  well 
  as 
  in 
  the 
  elevators 
  at 
  other 
  places 
  this 
  method 
  of 
  cleaning 
  

   the 
  grain 
  is 
  resorted 
  to. 
  It 
  may 
  be 
  effective 
  in 
  removing 
  the 
  adults, 
  

   but 
  the 
  fact 
  that 
  the 
  wheat 
  in 
  the 
  elevator 
  was 
  attacked 
  the 
  very 
  first 
  

   time 
  it 
  was 
  stored 
  showed 
  that 
  this 
  operation 
  does 
  not 
  remove 
  the 
  

   eggs, 
  larvae 
  and 
  such 
  pupse 
  as 
  pupate 
  inside 
  the 
  grain 
  (1). 
  

  

  3. 
  Superheating 
  : 
  — 
  By 
  this 
  method 
  all 
  the 
  stages 
  of 
  insects 
  attacking 
  

   the 
  grain 
  are 
  killed 
  and 
  the 
  grain 
  thus 
  cleaned 
  is 
  stored 
  in 
  insect-proof 
  

   bins. 
  It 
  is 
  chiefly 
  with 
  this 
  method 
  that 
  the 
  present 
  paper 
  deals. 
  

  

  From 
  the 
  above 
  it 
  will 
  appear 
  that 
  so 
  f- 
  r 
  no 
  really 
  satisfactory 
  method, 
  

   which 
  may 
  be 
  recommended 
  generally, 
  has 
  been 
  discovered. 
  " 
  There 
  

   is 
  no 
  treatment 
  known 
  that 
  can 
  immunize 
  the 
  grain 
  against 
  the 
  insects 
  

   even 
  for 
  a 
  few 
  months." 
  (5, 
  p. 
  756). 
  Barnes 
  and 
  Grove 
  after 
  a 
  series 
  

   of 
  experiments 
  came 
  to 
  the 
  conclusion 
  that 
  the 
  damage 
  fiom 
  wheat 
  

  

  