﻿102 
  PROCEEDINGS 
  OF 
  THE 
  FOrRTH 
  ENTOMOLOGICAL 
  MEETING 
  

  

  In 
  the 
  year 
  1912 
  about 
  50 
  lbs. 
  of 
  caterpillars 
  were 
  similarly 
  collected 
  

   and 
  destroyed. 
  

  

  (b) 
  In 
  the 
  third 
  year 
  (1913) 
  another 
  cheap 
  and 
  effective 
  contrivance 
  

   of 
  collecting 
  these 
  caterpillars 
  by 
  sweeping 
  a 
  grasshopper 
  bag 
  over 
  low 
  

   crops 
  as 
  well 
  as 
  in 
  grass 
  over 
  boundaries 
  was 
  introduced, 
  which 
  collected 
  

   from 
  an 
  area 
  of 
  about 
  8 
  acres, 
  30 
  lbs, 
  of 
  caterpillars 
  at 
  a 
  cost 
  of 
  0-3-3 
  

   per 
  acre 
  in 
  comparison 
  with 
  that 
  of 
  handpicking 
  which 
  cost 
  0-8-6 
  per 
  

   acre 
  to 
  collect 
  that 
  much 
  quantity 
  from 
  the 
  equal 
  area. 
  

  

  (c) 
  Another 
  contrivance 
  of 
  preventing 
  these 
  caterpillars 
  from 
  getting 
  

   from 
  one 
  field 
  to 
  another 
  by 
  means 
  of 
  simple 
  trenching 
  was 
  tried 
  but 
  this 
  

   did 
  not 
  prove 
  successful 
  owing 
  to 
  the 
  following 
  reasons. 
  First 
  the 
  

   advance 
  making 
  of 
  the 
  trench 
  in 
  summer 
  by 
  hand 
  digging 
  proved 
  very 
  

   costly 
  in 
  light 
  Goradu 
  soil 
  with 
  subsequent 
  fear 
  of 
  its 
  being 
  breached 
  

  

  -and 
  filled 
  with 
  earth 
  at 
  each 
  shower 
  of 
  heavy 
  rain. 
  It 
  cost 
  nearly 
  Rs. 
  3 
  

   for 
  making 
  it 
  round 
  about 
  a 
  plot 
  of 
  an 
  acre 
  with 
  a 
  trench 
  of 
  1 
  foot 
  deep 
  

   and 
  1 
  foot 
  6 
  inches 
  broad 
  at 
  the 
  surface 
  with 
  sides 
  sloping. 
  But 
  instead 
  

   of 
  that 
  if 
  a 
  trench 
  is 
  being 
  made 
  by 
  means 
  of 
  an 
  iron 
  G-allom 
  or 
  Turnwrest 
  

   plough 
  in 
  the 
  beginning 
  of 
  the 
  monsoon 
  after 
  about 
  4 
  to 
  5 
  inches 
  of 
  rain 
  

   have 
  fallen, 
  it 
  can 
  be 
  very 
  easily 
  made 
  at 
  a 
  very 
  low 
  cost 
  with 
  a 
  slight 
  

   repair 
  of 
  the 
  same. 
  Such 
  a 
  trench 
  was 
  made 
  in 
  the 
  year 
  1914 
  round 
  

   about 
  a 
  plot 
  of 
  3 
  acres 
  of 
  Bajri 
  and 
  Kadra 
  crop 
  at 
  Nadiad. 
  This 
  was 
  

   being 
  made 
  by 
  means 
  of 
  a 
  CT2 
  plough 
  with 
  two 
  pairs 
  of 
  bullocks. 
  It 
  

   measured 
  1,524 
  feet 
  in 
  length, 
  10 
  inches 
  broad 
  and 
  6 
  inches 
  deep 
  and 
  

   required 
  about 
  20 
  minutes 
  to 
  make 
  it. 
  By 
  a 
  heavier 
  plough 
  it 
  could 
  be 
  

   made 
  still 
  deeper 
  and 
  broader. 
  However 
  the 
  caterpillars 
  entering 
  such 
  

   an 
  empty 
  trench 
  from 
  its 
  one 
  side 
  will 
  very 
  easily 
  crawl 
  over 
  it 
  and 
  

   go 
  to 
  the 
  other 
  side. 
  To 
  prevent 
  them 
  from 
  doing 
  so, 
  if 
  the 
  bottom 
  

   of 
  the 
  trench 
  is 
  strewn 
  with 
  Cactus 
  leaves, 
  green 
  weeded 
  stuff 
  and 
  

   grass 
  in 
  the 
  evening, 
  they 
  remain 
  in 
  the 
  trench 
  partly 
  feeding 
  and 
  

   partly 
  concealed 
  under 
  it, 
  from 
  whence 
  they 
  could 
  be 
  easily 
  picked 
  

   up 
  and 
  destroyed 
  in 
  the 
  morning. 
  

  

  (d) 
  Spraying 
  trials 
  of 
  Lead 
  Chromate, 
  Lead 
  Arsenate 
  and 
  London 
  

   Purple 
  were 
  made 
  of 
  different 
  strengths 
  but 
  these 
  did 
  not 
  seem 
  to 
  respond 
  

   very 
  well 
  and 
  in 
  stronger 
  doses 
  of 
  London 
  Purple 
  even 
  with 
  an 
  admixture 
  

   of 
  quicklime, 
  it 
  used 
  to 
  scorch 
  the 
  leaves. 
  The 
  following 
  strength 
  of 
  

   insecticide 
  was 
  used 
  : 
  — 
  

  

  Lead 
  arsenate 
  paste 
  or 
  powder 
  . 
  . 
  . 
  . 
  , 
  1 
  to 
  2 
  oz. 
  

  

  Jaggery 
  . 
  , 
  . 
  , 
  , 
  , 
  . 
  . 
  , 
  6 
  oz. 
  

  

  Quicklime 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  . 
  3 
  oz. 
  

  

  Water 
  ......... 
  4: 
  gallons. 
  

  

  The 
  above 
  strength 
  of 
  the 
  solution 
  was 
  prepared 
  and 
  a 
  crop 
  of 
  Sann 
  

   ■was 
  sprayed 
  with 
  it 
  as 
  well 
  as 
  the 
  leaves 
  of 
  the 
  same 
  crop 
  were 
  dipped 
  iij 
  

  

  