﻿U.—JUAR 
  STEM-BORERS 
  {CHILO 
  SIMPLEX 
  AND 
  SESAMI 
  A 
  

  

  INFERENS). 
  

  

  By 
  T. 
  N. 
  Jhaveri, 
  L.Ag., 
  Entomological 
  Assistant, 
  Bombay. 
  

  

  These 
  are 
  the 
  species 
  which 
  are 
  principally 
  responsible 
  for 
  so 
  much 
  

   deterioration 
  of 
  the 
  monsoon 
  crop 
  of 
  Sorghum 
  in 
  the 
  Surat 
  district. 
  

   Of 
  the 
  two 
  species, 
  Chilo 
  is 
  mainly 
  responsible 
  for 
  attacking 
  the 
  crop 
  

   in 
  its 
  seedling 
  stage, 
  on 
  account 
  of 
  which 
  the 
  cultivators 
  are 
  required 
  

   at 
  times 
  to 
  resow 
  their 
  crops 
  once 
  or 
  twice. 
  In 
  a 
  normal 
  year 
  their 
  

   depredations 
  are 
  not 
  so 
  severe. 
  At 
  that 
  time 
  if 
  proper 
  investigations 
  

   are 
  being 
  made, 
  one 
  will 
  notice 
  a 
  large 
  number 
  of 
  " 
  Tachinid 
  " 
  fly 
  para- 
  

   sites 
  playing 
  a 
  very 
  important 
  part 
  in 
  controlling 
  this 
  pest 
  ; 
  but 
  in 
  the 
  

   subsequent 
  year 
  of 
  famine, 
  it 
  has 
  been 
  chiefly 
  found 
  that 
  this 
  borer- 
  

   attack 
  in 
  the 
  crop 
  is 
  very 
  severe 
  and 
  the 
  percentage 
  of 
  parasites 
  is 
  very 
  

   low 
  in 
  the 
  beginning. 
  That 
  is, 
  in 
  the 
  first 
  two 
  months 
  of 
  the 
  crop, 
  in 
  

   July 
  and 
  August 
  and 
  at 
  times 
  in 
  September, 
  the 
  attack 
  of 
  this 
  borer 
  

   is 
  very 
  severe, 
  but 
  later 
  on 
  in 
  September 
  the 
  parasites 
  begin 
  to 
  out- 
  

   number 
  the 
  pest 
  to 
  such 
  an 
  extent 
  that 
  about 
  the 
  beginning 
  of 
  November 
  

   this 
  Chilo 
  appears 
  to 
  have 
  been 
  totally 
  annihilated 
  and 
  hardly 
  any 
  

   caterpillars 
  of 
  the 
  same 
  are 
  being 
  found 
  in 
  the 
  stalk. 
  While 
  this 
  is 
  

   going 
  on, 
  the 
  other 
  kind 
  of 
  borer, 
  namely 
  Sesamia, 
  begins 
  to 
  gain 
  

   ground. 
  It 
  is 
  rather 
  slight 
  in 
  September 
  but 
  in 
  October-November, 
  

   it 
  greatly 
  increases 
  and 
  rests 
  in 
  the 
  caterpillar 
  stage 
  in 
  the 
  months 
  of 
  

   December 
  and 
  January, 
  depending 
  upon 
  the 
  severity 
  of 
  winter. 
  This 
  

   second 
  borer 
  is 
  not 
  preyed 
  upon 
  and 
  controlled 
  by 
  fly 
  parasites 
  and 
  

   in 
  winter 
  this 
  fly 
  parasite 
  does 
  not 
  breed. 
  In 
  summer, 
  this 
  second 
  

   borer 
  breeds 
  in 
  sprouted 
  shoots 
  coming 
  out 
  from 
  the 
  sides 
  of 
  jiiar 
  

   stumps 
  remaining 
  in 
  the 
  ground. 
  

  

  Taking 
  the 
  above 
  points 
  of 
  their 
  lifehistory 
  and 
  habitat 
  into 
  consi- 
  

   deration, 
  the 
  following 
  measures 
  were 
  tried 
  for 
  these 
  pests 
  :- 
  — 
  

  

  1. 
  The 
  first 
  measure 
  that 
  was 
  being 
  adopted 
  in 
  controlling 
  the 
  

   caterpillars 
  of 
  Chilo 
  was 
  the 
  removal 
  of 
  affected 
  plants 
  of 
  ji:ar 
  with 
  

   dead-hearts 
  at 
  the 
  first 
  and 
  second 
  thinnings 
  of 
  the 
  crop. 
  It 
  is 
  generally 
  

   the 
  practice 
  in 
  that 
  part 
  to 
  make 
  the 
  sowing 
  thick 
  in 
  the 
  beginning. 
  

   When 
  the 
  crop 
  has 
  grown 
  about 
  a 
  foot 
  to 
  a 
  foot-and-a-half 
  tall, 
  the 
  

   first 
  thinning 
  is 
  given, 
  which 
  comes 
  after 
  a 
  period 
  of 
  about 
  three 
  to 
  four 
  

   weeks 
  from 
  the 
  date 
  of 
  sowing 
  and 
  the 
  second 
  thinning 
  is 
  made 
  two 
  

  

  - 
  ( 
  143 
  ) 
  

  

  