﻿31.— 
  PRELIMINARY 
  OBSERVATIONS 
  ON 
  LETHAL 
  TEMPERA- 
  

   TURES 
  FOR 
  THE 
  LARViE 
  OF 
  TROGODERMA 
  KHAPRA, 
  A 
  

   PEST 
  OF 
  STORED 
  WHEAT. 
  

  

  (Plates 
  XLI— 
  XLIII). 
  

  

  Btj 
  M. 
  Afzal 
  Husain, 
  M.Sc. 
  (Pb)., 
  M.A. 
  (Cantab.), 
  I.A.S., 
  E?itomolo- 
  

   gist 
  to 
  Government, 
  Punjab, 
  and 
  Harnam 
  Dass 
  Bhasin, 
  M.Sc. 
  

   Demo7istrator 
  in 
  Zoology, 
  the 
  Punjab 
  Agricultural 
  College, 
  Lyallfur. 
  

  

  In 
  spite 
  of 
  the 
  marvellous 
  achievements 
  of 
  science 
  in 
  its 
  application 
  

   to 
  human 
  welfare, 
  the 
  problem 
  of 
  the 
  safety 
  of 
  our 
  daily 
  bread 
  still 
  

   remains 
  unsolved, 
  and 
  the 
  surest 
  method 
  of 
  successful 
  storage 
  of 
  wheat 
  

   grain 
  awaits 
  discovery. 
  

  

  Taking 
  the 
  damage 
  done 
  by 
  insects 
  to 
  stored 
  wheat 
  at 
  5 
  j)er 
  cent., 
  

   we 
  find 
  that 
  in 
  1918 
  the 
  Punjab 
  alone 
  lost 
  4,710,062-5 
  maunds 
  of 
  this 
  

   valuable 
  foodstuff, 
  or, 
  in 
  other 
  words, 
  paid 
  Rs. 
  235 
  laMis 
  as 
  tax 
  to 
  these 
  

   six-legged 
  creatures. 
  It 
  is 
  therefore 
  imperative 
  for 
  us 
  to 
  fight 
  these 
  

   insects 
  and 
  save 
  this 
  quantity 
  of 
  wheat, 
  which 
  is 
  sufficient 
  to 
  feed 
  about 
  

   1,032,343 
  people 
  for 
  one 
  year. 
  

  

  In 
  safe 
  storage 
  of 
  grain 
  we 
  are 
  concerned 
  with 
  two 
  distinct 
  problems 
  

   which 
  require 
  different 
  measures 
  to 
  solve 
  them 
  : 
  — 
  

  

  (i) 
  the 
  grain 
  to 
  be 
  stored 
  should 
  be 
  made 
  free 
  from 
  all 
  stages 
  of 
  

  

  insects, 
  and, 
  

   (m) 
  the 
  grain 
  stored 
  should 
  be 
  A(?2>'^ 
  free 
  from 
  insects. 
  All 
  the 
  methods 
  

  

  employed 
  to 
  achieve 
  these 
  ends 
  can 
  be 
  grouped 
  under 
  two 
  

  

  distinct 
  categories.* 
  

  

  A. 
  In 
  the 
  first 
  category 
  we 
  include 
  all 
  those 
  methods 
  which 
  aim 
  at 
  

   freeing 
  the 
  grain 
  from 
  insects 
  and 
  keeping 
  it 
  free 
  from 
  insects 
  in 
  a 
  single 
  

   operation. 
  What 
  is 
  claimed 
  for 
  these 
  methods 
  is 
  that 
  all 
  the 
  stages 
  of 
  

   the 
  insects 
  that 
  may 
  be 
  present 
  either 
  die 
  or 
  leave 
  the 
  grain, 
  and 
  fresh 
  

   introduction 
  is 
  made 
  impossible 
  either 
  by 
  chemical 
  or 
  mechanical 
  means. 
  

   Some 
  of 
  the 
  methods 
  that 
  fall 
  under 
  this 
  head 
  are 
  : 
  — 
  

  

  1. 
  The 
  use 
  of 
  Napthaline 
  balls 
  : 
  — 
  Grove 
  maintains 
  that 
  all 
  the 
  stages 
  

   of 
  insects 
  present 
  in 
  the 
  grain 
  are 
  killed 
  by 
  keeping 
  napthaline 
  balls 
  in 
  

   the 
  grain. 
  This 
  acts 
  as 
  a 
  deterrent 
  and 
  stops 
  further 
  infections 
  (10). 
  

   This 
  method, 
  however, 
  does 
  not 
  seem 
  to 
  be 
  very 
  effective 
  as 
  the 
  pests 
  

   are 
  said 
  to 
  appear 
  in 
  spite 
  of 
  this 
  precaution 
  (5). 
  

  

  * 
  Various 
  methods 
  of 
  grain 
  storage 
  that 
  have 
  been 
  in 
  vogue 
  in 
  India 
  are 
  described 
  

   at 
  length 
  bv 
  Fletcher 
  and 
  Ohosh 
  {Bejwrl 
  of 
  the 
  Third 
  Entomological 
  Meeting 
  held 
  at 
  

   Pusa 
  1919,'Yol 
  II, 
  pp., 
  725-733). 
  

  

  ( 
  240 
  ) 
  

  

  