﻿74 
  

  

  PROCEEDINGS 
  OF 
  THE 
  FOUETH 
  ENTOilOLOGICAL 
  MEETING 
  

  

  (3) 
  By 
  causing 
  premature 
  opening 
  of 
  the 
  boll 
  and 
  invasion 
  of 
  

  

  saprophytic 
  fungi, 
  Nigrosporum 
  and 
  others. 
  

  

  (4) 
  By 
  staining 
  the 
  lint 
  both 
  in 
  the 
  gin 
  and 
  in 
  the 
  boll. 
  

  

  (5) 
  As 
  pointed 
  out 
  by 
  Gough 
  (^), 
  by 
  lowering 
  the 
  germination 
  power 
  

  

  of 
  un-attacked 
  seeds 
  in 
  an 
  attacked 
  boll 
  (see 
  table 
  V). 
  

  

  The 
  number 
  of 
  seeds 
  destroyed 
  in 
  each 
  boll 
  varies 
  very 
  much. 
  Some- 
  

   times 
  all 
  five 
  locks 
  or 
  all 
  three 
  locks 
  will 
  be 
  destroyed, 
  sometimes 
  only 
  

   one, 
  and 
  the 
  remainder 
  produce 
  what 
  appear 
  to 
  be 
  good 
  lint 
  and 
  seeds. 
  

  

  The 
  number 
  of 
  attacked 
  bolls 
  at 
  any 
  given 
  date 
  does 
  not 
  give 
  one 
  

   any 
  accurate 
  idea 
  of 
  the 
  cash 
  value 
  of 
  the 
  damage 
  done 
  nor 
  of 
  the 
  extent 
  

   of 
  the 
  infestation. 
  

  

  At 
  the 
  time 
  of 
  the 
  first 
  picking 
  this 
  year 
  (March 
  1920) 
  examination 
  

   showed 
  that 
  out 
  of 
  100 
  bolls 
  containing 
  approximately 
  2,900 
  seeds 
  (a 
  

   Cambodia 
  boll 
  averages 
  28-30 
  seeds 
  per 
  boll) 
  only 
  14 
  seeds 
  were 
  

   destroyed, 
  that 
  is, 
  in 
  all 
  exactly 
  half 
  a 
  boll. 
  The 
  number 
  of 
  bolls 
  

   damaged 
  or 
  in 
  which 
  P. 
  gossypiella 
  was 
  found 
  were 
  three. 
  Therefore 
  

   in 
  this 
  case 
  the 
  percentage 
  of 
  bolls 
  damaged 
  equals 
  3 
  per 
  cent, 
  and 
  

   damage 
  to 
  seed 
  approximately 
  5 
  per 
  cent. 
  This 
  example 
  is 
  given 
  just 
  

   to 
  show 
  that 
  the 
  number 
  of 
  bolls 
  attacked 
  can 
  only 
  give 
  a 
  general 
  

   idea 
  of 
  the 
  actual 
  amount 
  of 
  damage. 
  On 
  the 
  other 
  hand 
  a 
  percentage 
  

   of 
  bolls 
  attacked 
  combined 
  with 
  a 
  percentage 
  of 
  boll-worm 
  population 
  

   gives 
  a 
  fairly 
  accurate 
  idea 
  of 
  the 
  degree 
  of 
  infestation. 
  

  

  It 
  must 
  also 
  be 
  remembered 
  that 
  towards 
  the 
  end 
  of 
  the 
  season 
  the 
  

   boll-worm 
  population 
  increases 
  to 
  a 
  tremendous 
  extent 
  and 
  that 
  as 
  

   many 
  as 
  eight 
  boll-worms 
  of 
  the 
  same 
  or 
  different 
  ages 
  will 
  be 
  found 
  

   in 
  one 
  boll, 
  whereas 
  at 
  the 
  beginning 
  of 
  the 
  season 
  this 
  multiple 
  infesta- 
  

   tion 
  is 
  rare. 
  Therefore 
  40 
  per 
  cent, 
  of 
  bolls 
  attacked 
  at 
  the 
  beginning 
  

   of 
  the 
  season 
  is 
  not 
  so 
  serious 
  a 
  loss 
  as 
  40 
  per 
  cent, 
  attacked 
  later 
  on. 
  

  

  Infestation 
  of 
  the 
  1918-19 
  crop. 
  The 
  first 
  lot 
  of 
  bolls 
  examined 
  was 
  

   from 
  a 
  lot 
  of 
  Cambodia 
  cotton 
  grown 
  in 
  the 
  wet 
  lands 
  belonging 
  to 
  the 
  

   Central 
  Farm 
  at 
  Coimbatore. 
  This 
  was 
  an 
  experimental 
  plot 
  of 
  about 
  

   an 
  acre 
  in 
  extent, 
  the 
  nearest 
  cotton 
  being 
  about 
  800 
  — 
  1,000 
  yards 
  

   away. 
  This 
  gave 
  the 
  following 
  results 
  : 
  — 
  

  

  