﻿INSECTS 
  IN 
  SUGAR-CANE 
  PLANTATIONS 
  IN 
  FIJI. 
  25 
  

  

  A 
  prolonged 
  effort 
  was 
  made 
  to 
  increase 
  the 
  efficiency 
  of 
  the 
  control 
  of 
  this 
  pest 
  by 
  

   the 
  introduction 
  of 
  a 
  Tachinid 
  fly 
  parasite, 
  Ceromasia 
  sphenophori, 
  Vill., 
  which 
  

   was 
  introduced 
  by 
  Mr. 
  F. 
  Muir 
  from 
  New 
  Guinea 
  to 
  Hawaii, 
  where 
  it 
  soon 
  brought 
  

   about 
  a 
  reduction 
  in 
  the 
  losses 
  on 
  the 
  plantations. 
  As 
  the 
  conditions 
  in 
  Fiji 
  appeared 
  

   to 
  be 
  favourable 
  to 
  the 
  introduction 
  of 
  the 
  parasite, 
  it 
  was 
  thought 
  possible 
  to 
  repeat 
  

   the 
  success, 
  and 
  accordingly 
  Dr. 
  J. 
  F. 
  Illing 
  worth, 
  of 
  the 
  College 
  of 
  Hawaii, 
  was 
  

   commissioned 
  by 
  the 
  Colonial 
  Sugar 
  Refining 
  Company 
  to 
  introduce 
  the 
  parasite 
  

   to 
  this 
  country. 
  He 
  arrived 
  on 
  30th 
  May 
  1913, 
  and 
  succeeded 
  in 
  rearing 
  the 
  parasite 
  

   inbreeding 
  cages, 
  from 
  which 
  he 
  liberated 
  large 
  colonies, 
  all 
  of 
  which 
  failed 
  to 
  become 
  

   established. 
  He 
  then 
  returned 
  to 
  Hawaii 
  after 
  spending 
  two 
  or 
  three 
  months 
  in 
  

   Fiji, 
  and 
  from 
  the 
  date 
  of 
  his 
  departure 
  until 
  the 
  end 
  of 
  1914 
  the 
  work 
  was 
  carried 
  

   on 
  by 
  Mr. 
  D. 
  S. 
  North 
  (Mycologist 
  to 
  the 
  Company) 
  ; 
  from 
  January 
  1915 
  to 
  March 
  

   1917 
  the 
  work 
  was 
  superintended 
  by 
  the 
  writer. 
  Mr. 
  North 
  was 
  successful 
  in 
  estab- 
  

   lishing 
  the 
  parasite 
  in 
  several 
  fields 
  on 
  Natova 
  plantation, 
  and 
  it 
  looked 
  as 
  if 
  success 
  

   was 
  in 
  sight, 
  but 
  unfortunately 
  this 
  field 
  colony 
  died 
  out 
  shortly 
  after 
  the 
  breeding 
  

   cage 
  on 
  the 
  plantation 
  was 
  closed. 
  The 
  writer's 
  experience 
  while 
  in 
  charge 
  of 
  the 
  

   work 
  was 
  similar 
  ; 
  so 
  long 
  as 
  the 
  breeding 
  cages 
  were 
  maintained, 
  it 
  was 
  possible 
  to 
  

   find 
  considerable 
  numbers 
  of 
  parasitised 
  borers 
  in 
  the 
  fields 
  adjoining 
  the 
  cages, 
  but 
  

   when 
  these 
  cages 
  were 
  closed 
  down 
  the 
  field 
  colonies 
  dwindled 
  and 
  eventually 
  died 
  

   out 
  ; 
  it 
  is 
  thus 
  evident 
  that 
  these 
  field 
  colonies 
  depended 
  for 
  their 
  continued 
  existence 
  

   on 
  a 
  steady 
  stream 
  of 
  new 
  parasites 
  from 
  the 
  breeding 
  cages 
  ; 
  when 
  that 
  steady 
  stream 
  

   ceased 
  the 
  rate 
  of 
  multiplication 
  in 
  the 
  field 
  seemed 
  unable 
  to 
  counterbalance 
  the 
  

   very 
  heavy 
  mortality 
  rate, 
  and 
  so 
  the 
  colonies 
  gradually 
  died 
  out. 
  The 
  effort 
  to 
  

   establish 
  the 
  parasite 
  lasted 
  almost 
  four 
  years, 
  and 
  ended 
  in 
  failure 
  in 
  spite 
  of 
  the 
  fact 
  

   that 
  very 
  large 
  colonies 
  were 
  liberated, 
  and 
  that 
  at 
  one 
  time 
  breeding 
  work 
  was 
  being 
  

   carried 
  on 
  at 
  five 
  different 
  centres 
  in 
  order 
  to 
  give 
  the 
  fly 
  a 
  trial 
  under 
  all 
  the 
  different 
  

   conditions 
  prevailing 
  in 
  the 
  sugar 
  districts. 
  This 
  failure 
  illustrates 
  the 
  uncertainty 
  

   of 
  all 
  parasite 
  work 
  ; 
  for 
  the 
  success 
  in 
  Hawaii 
  seemed 
  to 
  assure 
  an 
  equally 
  favourable 
  

   result 
  in 
  Fiji. 
  Climatic 
  conditions 
  cannot 
  be 
  held 
  responsible 
  for 
  the 
  failure, 
  for 
  the 
  

   parasite 
  was 
  bred 
  in 
  very 
  large 
  numbers 
  in 
  captivity, 
  clearly 
  showing 
  that 
  the 
  climate 
  

   was 
  favourable. 
  The 
  writer 
  is 
  of 
  opinion 
  that 
  the 
  large 
  jumping 
  spiders 
  and 
  the 
  

   small 
  brown 
  ants, 
  combined 
  with 
  peculiarities 
  in 
  agricultural 
  methods 
  and 
  in 
  the 
  

   growth 
  habits 
  of 
  the 
  leading 
  variety 
  of 
  cane, 
  have 
  been 
  responsible 
  for 
  this 
  disappoint- 
  

   ing 
  and 
  unexpected 
  result. 
  

  

  The 
  ease 
  with 
  which 
  this 
  parasite 
  establishes 
  itself 
  when 
  conditions 
  are 
  favourable 
  is 
  

   shown 
  by 
  the 
  fact 
  that 
  it 
  became 
  established 
  in 
  North 
  Queensland 
  from 
  a 
  few 
  flies 
  

   that 
  escaped 
  from 
  an 
  intermediate 
  breeding 
  cage 
  used 
  by 
  Muir 
  and 
  Kershaw 
  when 
  

   they 
  were 
  transporting 
  the 
  parasite 
  from 
  New 
  Guinea 
  to 
  Hawaii. 
  

  

  The 
  Small 
  Cane 
  Beetle 
  Borer 
  (Trochorrhopalus 
  stmngulatus, 
  Gyl.) 
  (fig 
  2). 
  

  

  This 
  weevil 
  is 
  frequently 
  found 
  in 
  cane. 
  It 
  is 
  much 
  smaller 
  than 
  the 
  more 
  des- 
  

   tructive 
  species, 
  from 
  which 
  it 
  can 
  be 
  easily 
  separated 
  in 
  the 
  larval, 
  pupal 
  and 
  adult 
  

   stages. 
  The 
  larva 
  of 
  the 
  larger 
  species 
  has 
  the 
  5th 
  and 
  6th 
  abdominal 
  segments 
  

   distinctly 
  swollen 
  ventrally, 
  a 
  feature 
  which 
  is 
  absent 
  in 
  this 
  insect 
  ; 
  and 
  in 
  the 
  pupal 
  

   stage 
  the 
  two 
  can 
  be 
  readily 
  separated 
  by 
  the 
  fact 
  that 
  the 
  smaller 
  species 
  does 
  not 
  

   make 
  a 
  cocoon. 
  The 
  adults 
  can 
  be 
  distinguished 
  by 
  their 
  colour, 
  the 
  smaller 
  species 
  

   being 
  unicolorous, 
  while 
  the 
  larger 
  one 
  has 
  its 
  brown 
  colouring 
  broken 
  by 
  black 
  

  

  