﻿118 
  rROCEEDlXGS 
  OF 
  THE 
  FOUimi 
  ENTOMOLOGICAL 
  MEETING 
  

  

  behaviour 
  of 
  the 
  fly 
  tliroiighoiit 
  the 
  year 
  still 
  remains 
  unsolved 
  and 
  

   obscure. 
  

  

  As 
  regards 
  control 
  we 
  have 
  got 
  the 
  following 
  facts 
  : 
  — 
  

  

  1. 
  In 
  1915 
  this 
  pest 
  occurred 
  extensively 
  in 
  the 
  neighbourhood 
  of 
  

   Ranchi 
  and 
  in 
  Khunti 
  Sub-division 
  of 
  the 
  Ranchi 
  district. 
  Mr. 
  A. 
  C 
  

   Dobbs, 
  Deputy 
  Director 
  of 
  Agriculture, 
  in 
  charge 
  of 
  this 
  area, 
  had 
  an 
  

   ■opportunity 
  of 
  keeping 
  this 
  area 
  under 
  his 
  observation 
  throughout 
  

   the 
  season. 
  In 
  the 
  middle 
  of 
  August 
  and 
  early 
  September 
  he 
  reported 
  

   extensive 
  damage. 
  In 
  the 
  second 
  week 
  of 
  September 
  the 
  \\Titer 
  visited 
  

   the 
  affected 
  area 
  near 
  Ranchi 
  and 
  found 
  that 
  certain 
  kinds 
  of 
  rice 
  and 
  

   certain 
  fields 
  newly 
  transplanted 
  were 
  affected 
  to 
  the 
  extent 
  of 
  about 
  

   5 
  to 
  50 
  per 
  cent. 
  In 
  November 
  Mr. 
  Dobbs 
  reported 
  as 
  follows 
  : 
  — 
  

   " 
  The 
  crop 
  at 
  Khunti 
  and 
  here 
  (Ranchi) 
  have 
  made 
  a 
  remarkable 
  recovery 
  

   owing 
  to 
  a 
  good 
  hathia 
  (rain) 
  and 
  it 
  looks 
  as 
  if 
  the 
  effect 
  of 
  the 
  attack 
  

   is 
  temporary 
  and 
  more 
  or 
  less 
  confined 
  to 
  the 
  shoots 
  attacked. 
  On 
  

   the 
  return 
  of 
  favourable 
  conditions 
  the 
  plants 
  throw 
  out 
  side 
  shoots 
  

   and 
  make 
  a 
  more 
  or 
  less 
  complete 
  recovery." 
  

  

  In 
  rice, 
  sugarcane 
  and 
  allied 
  plants 
  whenever 
  a 
  growing 
  point 
  is 
  

   damaged, 
  further 
  growth 
  is 
  stopped. 
  But 
  if 
  the 
  conditions 
  be 
  favour- 
  

   able 
  the 
  plants 
  always 
  make 
  an 
  attempt 
  to 
  compensate 
  the 
  loss 
  by 
  

   throwing 
  up 
  side-shoots 
  and 
  tillers. 
  In 
  Bengal, 
  the 
  cultivators 
  apply 
  

   Khari 
  nun 
  (crude 
  sodium 
  sulphate) 
  in 
  fields 
  affected 
  by 
  this 
  disease 
  

   and 
  they 
  assert 
  that 
  it 
  checks 
  the 
  disease. 
  The 
  explanation 
  seems 
  

   to 
  be 
  that 
  the 
  growth 
  of 
  the 
  plants 
  is 
  stimulated 
  and 
  recovery 
  takes 
  

   place 
  owing 
  to 
  the 
  development 
  of 
  tillers 
  and 
  side-shoots. 
  

  

  2. 
  During 
  the 
  outbreak 
  of 
  1915 
  in 
  the 
  Ranchi 
  district 
  it 
  was 
  observed 
  

   that 
  broad-casted 
  paddy 
  sown 
  in 
  April, 
  May 
  or 
  June, 
  and 
  therefore 
  

   much 
  advanced 
  in 
  growth 
  at 
  the 
  time 
  of 
  the 
  writer's 
  visit 
  in 
  the 
  second 
  

   week 
  of 
  September, 
  was 
  practically 
  immune 
  (their 
  young 
  side-shoots 
  

   being 
  affected 
  to 
  a 
  small 
  extent) 
  compared 
  with 
  the 
  late-transplanted 
  

   young 
  seedlings. 
  Transplantation 
  was 
  still 
  going 
  on 
  at 
  the 
  time. 
  

   Therefore 
  it 
  seems 
  that 
  carrying 
  out 
  of 
  the 
  transplanting 
  operations 
  

   •early 
  in 
  the 
  season 
  would 
  be 
  a 
  preventive 
  but 
  this 
  is 
  entirely 
  dependent 
  

   upon 
  the 
  prevalence 
  or 
  otherwise 
  of 
  favourable 
  climatic 
  conditions. 
  

  

  3. 
  There 
  is 
  a 
  minute 
  black 
  parasitic 
  wasp 
  {Platygaster 
  oryzw) 
  which 
  

   seems 
  to 
  keep 
  the 
  pest 
  in 
  check. 
  In 
  some 
  years 
  however 
  and 
  in 
  some 
  

   localities 
  owing 
  to 
  unknown 
  reasons 
  the 
  number 
  of 
  the 
  parasites 
  de- 
  

   creaises, 
  resulting 
  in 
  a 
  corresponding 
  increase 
  in 
  the 
  number 
  of 
  the 
  fly 
  

   Avith 
  more 
  damage 
  to 
  paddy 
  as 
  a 
  consequence. 
  At 
  Ranchi 
  in 
  the 
  second 
  

   week 
  of 
  September 
  1915 
  only 
  about 
  one 
  per 
  cent, 
  of 
  the 
  maggots 
  was 
  

   observed 
  to 
  be 
  parasitized. 
  In 
  Madras 
  in 
  1913 
  and 
  again 
  in 
  1914 
  (years 
  

   of 
  normal 
  slight 
  infestation) 
  the 
  maggots 
  were 
  parasitized 
  to 
  such 
  an 
  

  

  